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Minor wording clarification: somebody took the word `sessionname:'
[u/mdw/putty] / ssh.c
CommitLineData
8df7a775 1#include <windows.h>
374330e2 2#include <stdio.h>
3#include <stdlib.h>
fb09bf1c 4#include <stdarg.h>
5#include <assert.h>
374330e2 6
7#include "putty.h"
dacbd0e8 8#include "tree234.h"
fb09bf1c 9#include "ssh.h"
374330e2 10
11#ifndef FALSE
12#define FALSE 0
13#endif
14#ifndef TRUE
15#define TRUE 1
16#endif
17
765c4200 18/* uncomment this for packet level debugging */
19/* #define DUMP_PACKETS */
20
fb09bf1c 21#define logevent(s) { logevent(s); \
67779be7 22 if ((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)) \
b4453f49 23 { fprintf(stderr, "%s\n", s); fflush(stderr); } }
fb09bf1c 24
3cd52910 25#define bombout(msg) ( ssh_state = SSH_STATE_CLOSED, \
4a8fc3c4 26 (s ? sk_close(s), s = NULL : 0), \
3cd52910 27 connection_fatal msg )
8d5de777 28
32874aea 29#define SSH1_MSG_DISCONNECT 1 /* 0x1 */
30#define SSH1_SMSG_PUBLIC_KEY 2 /* 0x2 */
31#define SSH1_CMSG_SESSION_KEY 3 /* 0x3 */
32#define SSH1_CMSG_USER 4 /* 0x4 */
33#define SSH1_CMSG_AUTH_RSA 6 /* 0x6 */
34#define SSH1_SMSG_AUTH_RSA_CHALLENGE 7 /* 0x7 */
35#define SSH1_CMSG_AUTH_RSA_RESPONSE 8 /* 0x8 */
36#define SSH1_CMSG_AUTH_PASSWORD 9 /* 0x9 */
37#define SSH1_CMSG_REQUEST_PTY 10 /* 0xa */
38#define SSH1_CMSG_WINDOW_SIZE 11 /* 0xb */
39#define SSH1_CMSG_EXEC_SHELL 12 /* 0xc */
40#define SSH1_CMSG_EXEC_CMD 13 /* 0xd */
41#define SSH1_SMSG_SUCCESS 14 /* 0xe */
42#define SSH1_SMSG_FAILURE 15 /* 0xf */
43#define SSH1_CMSG_STDIN_DATA 16 /* 0x10 */
44#define SSH1_SMSG_STDOUT_DATA 17 /* 0x11 */
45#define SSH1_SMSG_STDERR_DATA 18 /* 0x12 */
46#define SSH1_CMSG_EOF 19 /* 0x13 */
47#define SSH1_SMSG_EXIT_STATUS 20 /* 0x14 */
48#define SSH1_MSG_CHANNEL_OPEN_CONFIRMATION 21 /* 0x15 */
49#define SSH1_MSG_CHANNEL_OPEN_FAILURE 22 /* 0x16 */
50#define SSH1_MSG_CHANNEL_DATA 23 /* 0x17 */
51#define SSH1_MSG_CHANNEL_CLOSE 24 /* 0x18 */
52#define SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION 25 /* 0x19 */
53#define SSH1_SMSG_X11_OPEN 27 /* 0x1b */
54#define SSH1_CMSG_PORT_FORWARD_REQUEST 28 /* 0x1c */
55#define SSH1_MSG_PORT_OPEN 29 /* 0x1d */
56#define SSH1_CMSG_AGENT_REQUEST_FORWARDING 30 /* 0x1e */
57#define SSH1_SMSG_AGENT_OPEN 31 /* 0x1f */
58#define SSH1_MSG_IGNORE 32 /* 0x20 */
59#define SSH1_CMSG_EXIT_CONFIRMATION 33 /* 0x21 */
60#define SSH1_CMSG_X11_REQUEST_FORWARDING 34 /* 0x22 */
61#define SSH1_CMSG_AUTH_RHOSTS_RSA 35 /* 0x23 */
62#define SSH1_MSG_DEBUG 36 /* 0x24 */
63#define SSH1_CMSG_REQUEST_COMPRESSION 37 /* 0x25 */
64#define SSH1_CMSG_AUTH_TIS 39 /* 0x27 */
65#define SSH1_SMSG_AUTH_TIS_CHALLENGE 40 /* 0x28 */
66#define SSH1_CMSG_AUTH_TIS_RESPONSE 41 /* 0x29 */
67#define SSH1_CMSG_AUTH_CCARD 70 /* 0x46 */
68#define SSH1_SMSG_AUTH_CCARD_CHALLENGE 71 /* 0x47 */
69#define SSH1_CMSG_AUTH_CCARD_RESPONSE 72 /* 0x48 */
70
71#define SSH1_AUTH_TIS 5 /* 0x5 */
72#define SSH1_AUTH_CCARD 16 /* 0x10 */
73
74#define SSH1_PROTOFLAG_SCREEN_NUMBER 1 /* 0x1 */
b96dc54c 75/* Mask for protoflags we will echo back to server if seen */
32874aea 76#define SSH1_PROTOFLAGS_SUPPORTED 0 /* 0x1 */
77
78#define SSH2_MSG_DISCONNECT 1 /* 0x1 */
79#define SSH2_MSG_IGNORE 2 /* 0x2 */
80#define SSH2_MSG_UNIMPLEMENTED 3 /* 0x3 */
81#define SSH2_MSG_DEBUG 4 /* 0x4 */
82#define SSH2_MSG_SERVICE_REQUEST 5 /* 0x5 */
83#define SSH2_MSG_SERVICE_ACCEPT 6 /* 0x6 */
84#define SSH2_MSG_KEXINIT 20 /* 0x14 */
85#define SSH2_MSG_NEWKEYS 21 /* 0x15 */
86#define SSH2_MSG_KEXDH_INIT 30 /* 0x1e */
87#define SSH2_MSG_KEXDH_REPLY 31 /* 0x1f */
88#define SSH2_MSG_KEX_DH_GEX_REQUEST 30 /* 0x1e */
89#define SSH2_MSG_KEX_DH_GEX_GROUP 31 /* 0x1f */
90#define SSH2_MSG_KEX_DH_GEX_INIT 32 /* 0x20 */
91#define SSH2_MSG_KEX_DH_GEX_REPLY 33 /* 0x21 */
92#define SSH2_MSG_USERAUTH_REQUEST 50 /* 0x32 */
93#define SSH2_MSG_USERAUTH_FAILURE 51 /* 0x33 */
94#define SSH2_MSG_USERAUTH_SUCCESS 52 /* 0x34 */
95#define SSH2_MSG_USERAUTH_BANNER 53 /* 0x35 */
96#define SSH2_MSG_USERAUTH_PK_OK 60 /* 0x3c */
97#define SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ 60 /* 0x3c */
98#define SSH2_MSG_GLOBAL_REQUEST 80 /* 0x50 */
99#define SSH2_MSG_REQUEST_SUCCESS 81 /* 0x51 */
100#define SSH2_MSG_REQUEST_FAILURE 82 /* 0x52 */
101#define SSH2_MSG_CHANNEL_OPEN 90 /* 0x5a */
102#define SSH2_MSG_CHANNEL_OPEN_CONFIRMATION 91 /* 0x5b */
103#define SSH2_MSG_CHANNEL_OPEN_FAILURE 92 /* 0x5c */
104#define SSH2_MSG_CHANNEL_WINDOW_ADJUST 93 /* 0x5d */
105#define SSH2_MSG_CHANNEL_DATA 94 /* 0x5e */
106#define SSH2_MSG_CHANNEL_EXTENDED_DATA 95 /* 0x5f */
107#define SSH2_MSG_CHANNEL_EOF 96 /* 0x60 */
108#define SSH2_MSG_CHANNEL_CLOSE 97 /* 0x61 */
109#define SSH2_MSG_CHANNEL_REQUEST 98 /* 0x62 */
110#define SSH2_MSG_CHANNEL_SUCCESS 99 /* 0x63 */
111#define SSH2_MSG_CHANNEL_FAILURE 100 /* 0x64 */
112
113#define SSH2_DISCONNECT_HOST_NOT_ALLOWED_TO_CONNECT 1 /* 0x1 */
114#define SSH2_DISCONNECT_PROTOCOL_ERROR 2 /* 0x2 */
115#define SSH2_DISCONNECT_KEY_EXCHANGE_FAILED 3 /* 0x3 */
116#define SSH2_DISCONNECT_HOST_AUTHENTICATION_FAILED 4 /* 0x4 */
117#define SSH2_DISCONNECT_MAC_ERROR 5 /* 0x5 */
118#define SSH2_DISCONNECT_COMPRESSION_ERROR 6 /* 0x6 */
119#define SSH2_DISCONNECT_SERVICE_NOT_AVAILABLE 7 /* 0x7 */
120#define SSH2_DISCONNECT_PROTOCOL_VERSION_NOT_SUPPORTED 8 /* 0x8 */
121#define SSH2_DISCONNECT_HOST_KEY_NOT_VERIFIABLE 9 /* 0x9 */
122#define SSH2_DISCONNECT_CONNECTION_LOST 10 /* 0xa */
123#define SSH2_DISCONNECT_BY_APPLICATION 11 /* 0xb */
124#define SSH2_DISCONNECT_TOO_MANY_CONNECTIONS 12 /* 0xc */
125#define SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER 13 /* 0xd */
126#define SSH2_DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE 14 /* 0xe */
127#define SSH2_DISCONNECT_ILLEGAL_USER_NAME 15 /* 0xf */
38c4a8da 128
129static const char *const ssh2_disconnect_reasons[] = {
130 NULL,
131 "SSH_DISCONNECT_HOST_NOT_ALLOWED_TO_CONNECT",
132 "SSH_DISCONNECT_PROTOCOL_ERROR",
133 "SSH_DISCONNECT_KEY_EXCHANGE_FAILED",
134 "SSH_DISCONNECT_HOST_AUTHENTICATION_FAILED",
135 "SSH_DISCONNECT_MAC_ERROR",
136 "SSH_DISCONNECT_COMPRESSION_ERROR",
137 "SSH_DISCONNECT_SERVICE_NOT_AVAILABLE",
138 "SSH_DISCONNECT_PROTOCOL_VERSION_NOT_SUPPORTED",
139 "SSH_DISCONNECT_HOST_KEY_NOT_VERIFIABLE",
140 "SSH_DISCONNECT_CONNECTION_LOST",
141 "SSH_DISCONNECT_BY_APPLICATION",
142 "SSH_DISCONNECT_TOO_MANY_CONNECTIONS",
143 "SSH_DISCONNECT_AUTH_CANCELLED_BY_USER",
144 "SSH_DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE",
145 "SSH_DISCONNECT_ILLEGAL_USER_NAME",
146};
9005f3ba 147
32874aea 148#define SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED 1 /* 0x1 */
149#define SSH2_OPEN_CONNECT_FAILED 2 /* 0x2 */
150#define SSH2_OPEN_UNKNOWN_CHANNEL_TYPE 3 /* 0x3 */
151#define SSH2_OPEN_RESOURCE_SHORTAGE 4 /* 0x4 */
d211621f 152
32874aea 153#define SSH2_EXTENDED_DATA_STDERR 1 /* 0x1 */
fb09bf1c 154
7d503c31 155/*
156 * Various remote-bug flags.
157 */
158#define BUG_CHOKES_ON_SSH1_IGNORE 1
159#define BUG_SSH2_HMAC 2
160
fb09bf1c 161#define GET_32BIT(cp) \
162 (((unsigned long)(unsigned char)(cp)[0] << 24) | \
163 ((unsigned long)(unsigned char)(cp)[1] << 16) | \
164 ((unsigned long)(unsigned char)(cp)[2] << 8) | \
165 ((unsigned long)(unsigned char)(cp)[3]))
166
167#define PUT_32BIT(cp, value) { \
168 (cp)[0] = (unsigned char)((value) >> 24); \
169 (cp)[1] = (unsigned char)((value) >> 16); \
170 (cp)[2] = (unsigned char)((value) >> 8); \
171 (cp)[3] = (unsigned char)(value); }
172
7cca0d81 173enum { PKT_END, PKT_INT, PKT_CHAR, PKT_DATA, PKT_STR, PKT_BIGNUM };
972a41c8 174
374330e2 175/* Coroutine mechanics for the sillier bits of the code */
176#define crBegin1 static int crLine = 0;
177#define crBegin2 switch(crLine) { case 0:;
178#define crBegin crBegin1; crBegin2;
179#define crFinish(z) } crLine = 0; return (z)
180#define crFinishV } crLine = 0; return
181#define crReturn(z) \
182 do {\
183 crLine=__LINE__; return (z); case __LINE__:;\
184 } while (0)
185#define crReturnV \
186 do {\
187 crLine=__LINE__; return; case __LINE__:;\
188 } while (0)
189#define crStop(z) do{ crLine = 0; return (z); }while(0)
190#define crStopV do{ crLine = 0; return; }while(0)
fb09bf1c 191#define crWaitUntil(c) do { crReturn(0); } while (!(c))
7cca0d81 192#define crWaitUntilV(c) do { crReturnV; } while (!(c))
374330e2 193
32874aea 194extern char *x11_init(Socket *, char *, void *);
195extern void x11_close(Socket);
196extern void x11_send(Socket, char *, int);
9c964e85 197extern void x11_invent_auth(char *, int, char *, int);
198
5e8358ad 199/*
200 * Ciphers for SSH2. We miss out single-DES because it isn't
201 * supported; also 3DES and Blowfish are both done differently from
202 * SSH1. (3DES uses outer chaining; Blowfish has the opposite
203 * endianness and different-sized keys.)
5e8358ad 204 */
0a3f1d48 205const static struct ssh2_ciphers *ciphers[] = {
206 &ssh2_aes,
207 &ssh2_blowfish,
208 &ssh2_3des,
8479e33c 209};
e5574168 210
a92dd380 211const static struct ssh_kex *kex_algs[] = {
a92dd380 212 &ssh_diffiehellman_gex,
32874aea 213 &ssh_diffiehellman
214};
e5574168 215
85cc02bb 216const static struct ssh_signkey *hostkey_algs[] = { &ssh_rsa, &ssh_dss };
e5574168 217
32874aea 218static void nullmac_key(unsigned char *key)
219{
220}
221static void nullmac_generate(unsigned char *blk, int len,
222 unsigned long seq)
223{
224}
225static int nullmac_verify(unsigned char *blk, int len, unsigned long seq)
226{
227 return 1;
228}
57476f6b 229const static struct ssh_mac ssh_mac_none = {
d39f364a 230 nullmac_key, nullmac_key, nullmac_generate, nullmac_verify, "none", 0
e5574168 231};
8b2715b2 232const static struct ssh_mac *macs[] = {
32874aea 233 &ssh_sha1, &ssh_md5, &ssh_mac_none
234};
8b2715b2 235const static struct ssh_mac *buggymacs[] = {
32874aea 236 &ssh_sha1_buggy, &ssh_md5, &ssh_mac_none
237};
e5574168 238
32874aea 239static void ssh_comp_none_init(void)
240{
241}
4ba9b64b 242static int ssh_comp_none_block(unsigned char *block, int len,
32874aea 243 unsigned char **outblock, int *outlen)
244{
245 return 0;
246}
247static int ssh_comp_none_disable(void)
248{
4ba9b64b 249 return 0;
250}
57476f6b 251const static struct ssh_compress ssh_comp_none = {
4ba9b64b 252 "none",
253 ssh_comp_none_init, ssh_comp_none_block,
63b00c83 254 ssh_comp_none_init, ssh_comp_none_block,
255 ssh_comp_none_disable
e5574168 256};
4ba9b64b 257extern const struct ssh_compress ssh_zlib;
258const static struct ssh_compress *compressions[] = {
32874aea 259 &ssh_zlib, &ssh_comp_none
260};
374330e2 261
32874aea 262enum { /* channel types */
783415f8 263 CHAN_MAINSESSION,
264 CHAN_X11,
265 CHAN_AGENT,
266};
267
dacbd0e8 268/*
269 * 2-3-4 tree storing channels.
270 */
271struct ssh_channel {
d211621f 272 unsigned remoteid, localid;
dacbd0e8 273 int type;
274 int closes;
783415f8 275 struct ssh2_data_channel {
32874aea 276 unsigned char *outbuffer;
277 unsigned outbuflen, outbufsize;
278 unsigned remwindow, remmaxpkt;
783415f8 279 } v2;
dacbd0e8 280 union {
32874aea 281 struct ssh_agent_channel {
282 unsigned char *message;
283 unsigned char msglen[4];
284 int lensofar, totallen;
285 } a;
286 struct ssh_x11_channel {
287 Socket s;
288 } x11;
dacbd0e8 289 } u;
290};
57476f6b 291
292struct Packet {
293 long length;
294 int type;
295 unsigned char *data;
296 unsigned char *body;
297 long savedpos;
298 long maxlen;
299};
300
0db56f73 301static SHA_State exhash, exhashbase;
57476f6b 302
8df7a775 303static Socket s = NULL;
57476f6b 304
305static unsigned char session_key[32];
4ba9b64b 306static int ssh1_compressing;
b96dc54c 307static int ssh1_remote_protoflags;
308static int ssh1_local_protoflags;
db7d555c 309static int ssh_agentfwd_enabled;
9c964e85 310static int ssh_X11_fwd_enabled;
7d503c31 311static int ssh_remote_bugs;
57476f6b 312static const struct ssh_cipher *cipher = NULL;
0a3f1d48 313static const struct ssh2_cipher *cscipher = NULL;
314static const struct ssh2_cipher *sccipher = NULL;
57476f6b 315static const struct ssh_mac *csmac = NULL;
316static const struct ssh_mac *scmac = NULL;
317static const struct ssh_compress *cscomp = NULL;
318static const struct ssh_compress *sccomp = NULL;
319static const struct ssh_kex *kex = NULL;
e055a386 320static const struct ssh_signkey *hostkey = NULL;
65a22376 321static unsigned char ssh2_session_id[20];
32874aea 322int (*ssh_get_line) (const char *prompt, char *str, int maxlen,
323 int is_pw) = NULL;
57476f6b 324
325static char *savedhost;
326static int savedport;
327static int ssh_send_ok;
0965bee0 328static int ssh_echoing, ssh_editing;
57476f6b 329
32874aea 330static tree234 *ssh_channels; /* indexed by local id */
57476f6b 331static struct ssh_channel *mainchan; /* primary session channel */
332
333static enum {
3687d221 334 SSH_STATE_PREPACKET,
57476f6b 335 SSH_STATE_BEFORE_SIZE,
336 SSH_STATE_INTERMED,
337 SSH_STATE_SESSION,
338 SSH_STATE_CLOSED
3687d221 339} ssh_state = SSH_STATE_PREPACKET;
57476f6b 340
3687d221 341static int size_needed = FALSE, eof_needed = FALSE;
57476f6b 342
343static struct Packet pktin = { 0, 0, NULL, NULL, 0 };
344static struct Packet pktout = { 0, 0, NULL, NULL, 0 };
b185170a 345static unsigned char *deferred_send_data = NULL;
346static int deferred_len = 0, deferred_size = 0;
57476f6b 347
348static int ssh_version;
32874aea 349static void (*ssh_protocol) (unsigned char *in, int inlen, int ispkt);
57476f6b 350static void ssh1_protocol(unsigned char *in, int inlen, int ispkt);
351static void ssh2_protocol(unsigned char *in, int inlen, int ispkt);
352static void ssh_size(void);
32874aea 353static void ssh_special(Telnet_Special);
783415f8 354static void ssh2_try_send(struct ssh_channel *c);
32874aea 355static void ssh2_add_channel_data(struct ssh_channel *c, char *buf,
356 int len);
57476f6b 357
32874aea 358static int (*s_rdpkt) (unsigned char **data, int *datalen);
57476f6b 359
360static struct rdpkt1_state_tag {
361 long len, pad, biglen, to_read;
362 unsigned long realcrc, gotcrc;
363 unsigned char *p;
364 int i;
365 int chunk;
366} rdpkt1_state;
367
960e736a 368static struct rdpkt2_state_tag {
369 long len, pad, payload, packetlen, maclen;
370 int i;
371 int cipherblk;
372 unsigned long incoming_sequence;
373} rdpkt2_state;
374
32874aea 375static int ssh_channelcmp(void *av, void *bv)
376{
377 struct ssh_channel *a = (struct ssh_channel *) av;
378 struct ssh_channel *b = (struct ssh_channel *) bv;
379 if (a->localid < b->localid)
380 return -1;
381 if (a->localid > b->localid)
382 return +1;
dacbd0e8 383 return 0;
384}
32874aea 385static int ssh_channelfind(void *av, void *bv)
386{
387 unsigned *a = (unsigned *) av;
388 struct ssh_channel *b = (struct ssh_channel *) bv;
389 if (*a < b->localid)
390 return -1;
391 if (*a > b->localid)
392 return +1;
dacbd0e8 393 return 0;
394}
395
32874aea 396static int alloc_channel_id(void)
397{
260f3dec 398 const unsigned CHANNEL_NUMBER_OFFSET = 256;
399 unsigned low, high, mid;
d2371c81 400 int tsize;
401 struct ssh_channel *c;
402
403 /*
404 * First-fit allocation of channel numbers: always pick the
405 * lowest unused one. To do this, binary-search using the
406 * counted B-tree to find the largest channel ID which is in a
407 * contiguous sequence from the beginning. (Precisely
408 * everything in that sequence must have ID equal to its tree
409 * index plus CHANNEL_NUMBER_OFFSET.)
410 */
411 tsize = count234(ssh_channels);
412
32874aea 413 low = -1;
414 high = tsize;
d2371c81 415 while (high - low > 1) {
416 mid = (high + low) / 2;
417 c = index234(ssh_channels, mid);
418 if (c->localid == mid + CHANNEL_NUMBER_OFFSET)
419 low = mid; /* this one is fine */
420 else
421 high = mid; /* this one is past it */
422 }
423 /*
424 * Now low points to either -1, or the tree index of the
425 * largest ID in the initial sequence.
426 */
427 {
428 unsigned i = low + 1 + CHANNEL_NUMBER_OFFSET;
429 assert(NULL == find234(ssh_channels, &i, ssh_channelfind));
430 }
431 return low + 1 + CHANNEL_NUMBER_OFFSET;
432}
433
32874aea 434static void c_write(char *buf, int len)
435{
67779be7 436 if ((flags & FLAG_STDERR)) {
32874aea 437 int i;
438 for (i = 0; i < len; i++)
439 if (buf[i] != '\r')
440 fputc(buf[i], stderr);
fb09bf1c 441 return;
442 }
fe50e814 443 from_backend(1, buf, len);
3bdaf79d 444}
445
32874aea 446static void c_write_untrusted(char *buf, int len)
447{
a209e957 448 int i;
449 for (i = 0; i < len; i++) {
32874aea 450 if (buf[i] == '\n')
451 c_write("\r\n", 2);
452 else if ((buf[i] & 0x60) || (buf[i] == '\r'))
453 c_write(buf + i, 1);
a209e957 454 }
455}
456
32874aea 457static void c_write_str(char *buf)
458{
1408a877 459 c_write(buf, strlen(buf));
460}
461
fb09bf1c 462/*
463 * Collect incoming data in the incoming packet buffer.
e5574168 464 * Decipher and verify the packet when it is completely read.
465 * Drop SSH1_MSG_DEBUG and SSH1_MSG_IGNORE packets.
fb09bf1c 466 * Update the *data and *datalen variables.
467 * Return the additional nr of bytes needed, or 0 when
468 * a complete packet is available.
469 */
e5574168 470static int ssh1_rdpkt(unsigned char **data, int *datalen)
fb09bf1c 471{
57476f6b 472 struct rdpkt1_state_tag *st = &rdpkt1_state;
374330e2 473
474 crBegin;
374330e2 475
32874aea 476 next_packet:
37508af4 477
fb09bf1c 478 pktin.type = 0;
479 pktin.length = 0;
374330e2 480
57476f6b 481 for (st->i = st->len = 0; st->i < 4; st->i++) {
fb09bf1c 482 while ((*datalen) == 0)
32874aea 483 crReturn(4 - st->i);
57476f6b 484 st->len = (st->len << 8) + **data;
fb09bf1c 485 (*data)++, (*datalen)--;
486 }
374330e2 487
fb09bf1c 488#ifdef FWHACK
32874aea 489 if (st->len == 0x52656d6f) { /* "Remo"te server has closed ... */
490 st->len = 0x300; /* big enough to carry to end */
fb09bf1c 491 }
492#endif
374330e2 493
57476f6b 494 st->pad = 8 - (st->len % 8);
495 st->biglen = st->len + st->pad;
496 pktin.length = st->len - 5;
fb09bf1c 497
57476f6b 498 if (pktin.maxlen < st->biglen) {
499 pktin.maxlen = st->biglen;
32874aea 500 pktin.data = (pktin.data == NULL ? smalloc(st->biglen + APIEXTRA) :
501 srealloc(pktin.data, st->biglen + APIEXTRA));
fb09bf1c 502 if (!pktin.data)
503 fatalbox("Out of memory");
504 }
374330e2 505
57476f6b 506 st->to_read = st->biglen;
507 st->p = pktin.data;
508 while (st->to_read > 0) {
32874aea 509 st->chunk = st->to_read;
fb09bf1c 510 while ((*datalen) == 0)
57476f6b 511 crReturn(st->to_read);
512 if (st->chunk > (*datalen))
513 st->chunk = (*datalen);
514 memcpy(st->p, *data, st->chunk);
515 *data += st->chunk;
516 *datalen -= st->chunk;
517 st->p += st->chunk;
518 st->to_read -= st->chunk;
fb09bf1c 519 }
374330e2 520
fb09bf1c 521 if (cipher)
57476f6b 522 cipher->decrypt(pktin.data, st->biglen);
765c4200 523#ifdef DUMP_PACKETS
524 debug(("Got packet len=%d pad=%d\n", st->len, st->pad));
525 dmemdump(pktin.data, st->biglen);
698a5108 526#endif
374330e2 527
32874aea 528 st->realcrc = crc32(pktin.data, st->biglen - 4);
529 st->gotcrc = GET_32BIT(pktin.data + st->biglen - 4);
57476f6b 530 if (st->gotcrc != st->realcrc) {
8d5de777 531 bombout(("Incorrect CRC received on packet"));
32874aea 532 crReturn(0);
fb09bf1c 533 }
572f871e 534
4ba9b64b 535 pktin.body = pktin.data + st->pad + 1;
536
537 if (ssh1_compressing) {
538 unsigned char *decompblk;
539 int decomplen;
765c4200 540#ifdef DUMP_PACKETS
541 debug(("Packet payload pre-decompression:\n"));
32874aea 542 dmemdump(pktin.body - 1, pktin.length + 1);
4ba9b64b 543#endif
32874aea 544 zlib_decompress_block(pktin.body - 1, pktin.length + 1,
4ba9b64b 545 &decompblk, &decomplen);
546
547 if (pktin.maxlen < st->pad + decomplen) {
548 pktin.maxlen = st->pad + decomplen;
32874aea 549 pktin.data = srealloc(pktin.data, pktin.maxlen + APIEXTRA);
550 pktin.body = pktin.data + st->pad + 1;
4ba9b64b 551 if (!pktin.data)
552 fatalbox("Out of memory");
553 }
554
32874aea 555 memcpy(pktin.body - 1, decompblk, decomplen);
dcbde236 556 sfree(decompblk);
32874aea 557 pktin.length = decomplen - 1;
765c4200 558#ifdef DUMP_PACKETS
559 debug(("Packet payload post-decompression:\n"));
32874aea 560 dmemdump(pktin.body - 1, pktin.length + 1);
4ba9b64b 561#endif
562 }
563
e5574168 564 if (pktin.type == SSH1_SMSG_STDOUT_DATA ||
32874aea 565 pktin.type == SSH1_SMSG_STDERR_DATA ||
566 pktin.type == SSH1_MSG_DEBUG ||
567 pktin.type == SSH1_SMSG_AUTH_TIS_CHALLENGE ||
568 pktin.type == SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
fb09bf1c 569 long strlen = GET_32BIT(pktin.body);
8d5de777 570 if (strlen + 4 != pktin.length) {
571 bombout(("Received data packet with bogus string length"));
32874aea 572 crReturn(0);
573 }
fb09bf1c 574 }
575
4ba9b64b 576 pktin.type = pktin.body[-1];
577
e5574168 578 if (pktin.type == SSH1_MSG_DEBUG) {
fb09bf1c 579 /* log debug message */
580 char buf[80];
581 int strlen = GET_32BIT(pktin.body);
582 strcpy(buf, "Remote: ");
32874aea 583 if (strlen > 70)
584 strlen = 70;
585 memcpy(buf + 8, pktin.body + 4, strlen);
586 buf[8 + strlen] = '\0';
fb09bf1c 587 logevent(buf);
588 goto next_packet;
e5574168 589 } else if (pktin.type == SSH1_MSG_IGNORE) {
fb09bf1c 590 /* do nothing */
591 goto next_packet;
592 }
593
38c4a8da 594 if (pktin.type == SSH1_MSG_DISCONNECT) {
595 /* log reason code in disconnect message */
596 char buf[256];
260f3dec 597 unsigned msglen = GET_32BIT(pktin.body);
598 unsigned nowlen;
38c4a8da 599 strcpy(buf, "Remote sent disconnect: ");
600 nowlen = strlen(buf);
32874aea 601 if (msglen > sizeof(buf) - nowlen - 1)
602 msglen = sizeof(buf) - nowlen - 1;
603 memcpy(buf + nowlen, pktin.body + 4, msglen);
604 buf[nowlen + msglen] = '\0';
38c4a8da 605 logevent(buf);
606 }
607
fb09bf1c 608 crFinish(0);
609}
610
e5574168 611static int ssh2_rdpkt(unsigned char **data, int *datalen)
612{
960e736a 613 struct rdpkt2_state_tag *st = &rdpkt2_state;
e5574168 614
615 crBegin;
616
32874aea 617 next_packet:
e5574168 618 pktin.type = 0;
619 pktin.length = 0;
960e736a 620 if (sccipher)
32874aea 621 st->cipherblk = sccipher->blksize;
e5574168 622 else
32874aea 623 st->cipherblk = 8;
960e736a 624 if (st->cipherblk < 8)
32874aea 625 st->cipherblk = 8;
960e736a 626
627 if (pktin.maxlen < st->cipherblk) {
628 pktin.maxlen = st->cipherblk;
32874aea 629 pktin.data =
630 (pktin.data ==
631 NULL ? smalloc(st->cipherblk +
632 APIEXTRA) : srealloc(pktin.data,
633 st->cipherblk +
634 APIEXTRA));
e5574168 635 if (!pktin.data)
636 fatalbox("Out of memory");
637 }
638
639 /*
640 * Acquire and decrypt the first block of the packet. This will
641 * contain the length and padding details.
642 */
32874aea 643 for (st->i = st->len = 0; st->i < st->cipherblk; st->i++) {
e5574168 644 while ((*datalen) == 0)
32874aea 645 crReturn(st->cipherblk - st->i);
960e736a 646 pktin.data[st->i] = *(*data)++;
32874aea 647 (*datalen)--;
e5574168 648 }
649#ifdef FWHACK
32874aea 650 if (!memcmp(pktin.data, "Remo", 4)) { /* "Remo"te server has closed ... */
651 /* FIXME */
e5574168 652 }
653#endif
654 if (sccipher)
32874aea 655 sccipher->decrypt(pktin.data, st->cipherblk);
e5574168 656
657 /*
658 * Now get the length and padding figures.
659 */
960e736a 660 st->len = GET_32BIT(pktin.data);
661 st->pad = pktin.data[4];
e5574168 662
663 /*
664 * This enables us to deduce the payload length.
665 */
960e736a 666 st->payload = st->len - st->pad - 1;
e5574168 667
960e736a 668 pktin.length = st->payload + 5;
e5574168 669
670 /*
671 * So now we can work out the total packet length.
672 */
960e736a 673 st->packetlen = st->len + 4;
674 st->maclen = scmac ? scmac->len : 0;
e5574168 675
676 /*
677 * Adjust memory allocation if packet is too big.
678 */
32874aea 679 if (pktin.maxlen < st->packetlen + st->maclen) {
680 pktin.maxlen = st->packetlen + st->maclen;
681 pktin.data =
682 (pktin.data ==
683 NULL ? smalloc(pktin.maxlen + APIEXTRA) : srealloc(pktin.data,
684 pktin.maxlen
685 +
686 APIEXTRA));
e5574168 687 if (!pktin.data)
688 fatalbox("Out of memory");
689 }
690
691 /*
692 * Read and decrypt the remainder of the packet.
693 */
32874aea 694 for (st->i = st->cipherblk; st->i < st->packetlen + st->maclen;
695 st->i++) {
e5574168 696 while ((*datalen) == 0)
960e736a 697 crReturn(st->packetlen + st->maclen - st->i);
698 pktin.data[st->i] = *(*data)++;
32874aea 699 (*datalen)--;
e5574168 700 }
701 /* Decrypt everything _except_ the MAC. */
702 if (sccipher)
32874aea 703 sccipher->decrypt(pktin.data + st->cipherblk,
704 st->packetlen - st->cipherblk);
e5574168 705
765c4200 706#ifdef DUMP_PACKETS
707 debug(("Got packet len=%d pad=%d\n", st->len, st->pad));
708 dmemdump(pktin.data, st->packetlen);
7cca0d81 709#endif
d39f364a 710
e5574168 711 /*
712 * Check the MAC.
713 */
32874aea 714 if (scmac
715 && !scmac->verify(pktin.data, st->len + 4,
716 st->incoming_sequence)) {
8d5de777 717 bombout(("Incorrect MAC received on packet"));
32874aea 718 crReturn(0);
8d5de777 719 }
32874aea 720 st->incoming_sequence++; /* whether or not we MACed */
e5574168 721
4ba9b64b 722 /*
723 * Decompress packet payload.
724 */
725 {
726 unsigned char *newpayload;
727 int newlen;
32874aea 728 if (sccomp && sccomp->decompress(pktin.data + 5, pktin.length - 5,
4ba9b64b 729 &newpayload, &newlen)) {
32874aea 730 if (pktin.maxlen < newlen + 5) {
731 pktin.maxlen = newlen + 5;
732 pktin.data =
733 (pktin.data ==
734 NULL ? smalloc(pktin.maxlen +
735 APIEXTRA) : srealloc(pktin.data,
736 pktin.maxlen +
737 APIEXTRA));
4ba9b64b 738 if (!pktin.data)
739 fatalbox("Out of memory");
740 }
741 pktin.length = 5 + newlen;
32874aea 742 memcpy(pktin.data + 5, newpayload, newlen);
765c4200 743#ifdef DUMP_PACKETS
744 debug(("Post-decompression payload:\n"));
32874aea 745 dmemdump(pktin.data + 5, newlen);
4ba9b64b 746#endif
747
dcbde236 748 sfree(newpayload);
4ba9b64b 749 }
750 }
751
e5574168 752 pktin.savedpos = 6;
753 pktin.type = pktin.data[5];
e5574168 754
7cca0d81 755 if (pktin.type == SSH2_MSG_IGNORE || pktin.type == SSH2_MSG_DEBUG)
32874aea 756 goto next_packet; /* FIXME: print DEBUG message */
e5574168 757
38c4a8da 758 if (pktin.type == SSH2_MSG_DISCONNECT) {
759 /* log reason code in disconnect message */
760 char buf[256];
32874aea 761 int reason = GET_32BIT(pktin.data + 6);
762 unsigned msglen = GET_32BIT(pktin.data + 10);
260f3dec 763 unsigned nowlen;
38c4a8da 764 if (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) {
765 sprintf(buf, "Received disconnect message (%s)",
766 ssh2_disconnect_reasons[reason]);
767 } else {
32874aea 768 sprintf(buf, "Received disconnect message (unknown type %d)",
769 reason);
38c4a8da 770 }
771 logevent(buf);
772 strcpy(buf, "Disconnection message text: ");
773 nowlen = strlen(buf);
32874aea 774 if (msglen > sizeof(buf) - nowlen - 1)
775 msglen = sizeof(buf) - nowlen - 1;
776 memcpy(buf + nowlen, pktin.data + 14, msglen);
777 buf[nowlen + msglen] = '\0';
38c4a8da 778 logevent(buf);
779 }
780
e5574168 781 crFinish(0);
782}
783
32874aea 784static void ssh1_pktout_size(int len)
785{
374330e2 786 int pad, biglen;
787
788 len += 5; /* type and CRC */
32874aea 789 pad = 8 - (len % 8);
374330e2 790 biglen = len + pad;
791
32874aea 792 pktout.length = len - 5;
374330e2 793 if (pktout.maxlen < biglen) {
794 pktout.maxlen = biglen;
8f203108 795#ifdef MSCRYPTOAPI
fb09bf1c 796 /* Allocate enough buffer space for extra block
8f203108 797 * for MS CryptEncrypt() */
32874aea 798 pktout.data = (pktout.data == NULL ? smalloc(biglen + 12) :
799 srealloc(pktout.data, biglen + 12));
8f203108 800#else
32874aea 801 pktout.data = (pktout.data == NULL ? smalloc(biglen + 4) :
802 srealloc(pktout.data, biglen + 4));
8f203108 803#endif
374330e2 804 if (!pktout.data)
805 fatalbox("Out of memory");
806 }
32874aea 807 pktout.body = pktout.data + 4 + pad + 1;
4ba9b64b 808}
374330e2 809
32874aea 810static void s_wrpkt_start(int type, int len)
811{
4ba9b64b 812 ssh1_pktout_size(len);
374330e2 813 pktout.type = type;
374330e2 814}
815
32874aea 816static int s_wrpkt_prepare(void)
817{
374330e2 818 int pad, len, biglen, i;
819 unsigned long crc;
820
4ba9b64b 821 pktout.body[-1] = pktout.type;
822
765c4200 823#ifdef DUMP_PACKETS
7d503c31 824 debug(("Packet payload pre-compression:\n"));
32874aea 825 dmemdump(pktout.body - 1, pktout.length + 1);
7d503c31 826#endif
827
4ba9b64b 828 if (ssh1_compressing) {
829 unsigned char *compblk;
830 int complen;
32874aea 831 zlib_compress_block(pktout.body - 1, pktout.length + 1,
4ba9b64b 832 &compblk, &complen);
32874aea 833 ssh1_pktout_size(complen - 1);
834 memcpy(pktout.body - 1, compblk, complen);
dcbde236 835 sfree(compblk);
765c4200 836#ifdef DUMP_PACKETS
4ba9b64b 837 debug(("Packet payload post-compression:\n"));
32874aea 838 dmemdump(pktout.body - 1, pktout.length + 1);
4ba9b64b 839#endif
840 }
841
374330e2 842 len = pktout.length + 5; /* type and CRC */
32874aea 843 pad = 8 - (len % 8);
374330e2 844 biglen = len + pad;
845
32874aea 846 for (i = 0; i < pad; i++)
847 pktout.data[i + 4] = random_byte();
848 crc = crc32(pktout.data + 4, biglen - 4);
849 PUT_32BIT(pktout.data + biglen, crc);
fb09bf1c 850 PUT_32BIT(pktout.data, len);
374330e2 851
765c4200 852#ifdef DUMP_PACKETS
32874aea 853 debug(("Sending packet len=%d\n", biglen + 4));
854 dmemdump(pktout.data, biglen + 4);
698a5108 855#endif
374330e2 856 if (cipher)
32874aea 857 cipher->encrypt(pktout.data + 4, biglen);
374330e2 858
32874aea 859 return biglen + 4;
39065bed 860}
861
32874aea 862static void s_wrpkt(void)
863{
39065bed 864 int len;
865 len = s_wrpkt_prepare();
866 sk_write(s, pktout.data, len);
867}
868
32874aea 869static void s_wrpkt_defer(void)
870{
39065bed 871 int len;
872 len = s_wrpkt_prepare();
873 if (deferred_len + len > deferred_size) {
32874aea 874 deferred_size = deferred_len + len + 128;
875 deferred_send_data = srealloc(deferred_send_data, deferred_size);
39065bed 876 }
32874aea 877 memcpy(deferred_send_data + deferred_len, pktout.data, len);
39065bed 878 deferred_len += len;
374330e2 879}
880
fb09bf1c 881/*
39065bed 882 * Construct a packet with the specified contents.
fb09bf1c 883 */
39065bed 884static void construct_packet(int pkttype, va_list ap1, va_list ap2)
fb09bf1c 885{
fb09bf1c 886 unsigned char *p, *argp, argchar;
887 unsigned long argint;
888 int pktlen, argtype, arglen;
7cca0d81 889 Bignum bn;
fb09bf1c 890
891 pktlen = 0;
39065bed 892 while ((argtype = va_arg(ap1, int)) != PKT_END) {
fb09bf1c 893 switch (argtype) {
894 case PKT_INT:
39065bed 895 (void) va_arg(ap1, int);
fb09bf1c 896 pktlen += 4;
897 break;
898 case PKT_CHAR:
39065bed 899 (void) va_arg(ap1, char);
fb09bf1c 900 pktlen++;
901 break;
902 case PKT_DATA:
39065bed 903 (void) va_arg(ap1, unsigned char *);
904 arglen = va_arg(ap1, int);
fb09bf1c 905 pktlen += arglen;
906 break;
907 case PKT_STR:
39065bed 908 argp = va_arg(ap1, unsigned char *);
fb09bf1c 909 arglen = strlen(argp);
910 pktlen += 4 + arglen;
911 break;
7cca0d81 912 case PKT_BIGNUM:
39065bed 913 bn = va_arg(ap1, Bignum);
32874aea 914 pktlen += ssh1_bignum_length(bn);
7cca0d81 915 break;
fb09bf1c 916 default:
917 assert(0);
918 }
919 }
fb09bf1c 920
921 s_wrpkt_start(pkttype, pktlen);
922 p = pktout.body;
923
39065bed 924 while ((argtype = va_arg(ap2, int)) != PKT_END) {
fb09bf1c 925 switch (argtype) {
926 case PKT_INT:
39065bed 927 argint = va_arg(ap2, int);
fb09bf1c 928 PUT_32BIT(p, argint);
929 p += 4;
930 break;
931 case PKT_CHAR:
39065bed 932 argchar = va_arg(ap2, unsigned char);
fb09bf1c 933 *p = argchar;
934 p++;
935 break;
936 case PKT_DATA:
39065bed 937 argp = va_arg(ap2, unsigned char *);
938 arglen = va_arg(ap2, int);
fb09bf1c 939 memcpy(p, argp, arglen);
940 p += arglen;
941 break;
942 case PKT_STR:
39065bed 943 argp = va_arg(ap2, unsigned char *);
fb09bf1c 944 arglen = strlen(argp);
945 PUT_32BIT(p, arglen);
946 memcpy(p + 4, argp, arglen);
947 p += 4 + arglen;
948 break;
7cca0d81 949 case PKT_BIGNUM:
39065bed 950 bn = va_arg(ap2, Bignum);
32874aea 951 p += ssh1_write_bignum(p, bn);
7cca0d81 952 break;
fb09bf1c 953 }
954 }
39065bed 955}
fb09bf1c 956
32874aea 957static void send_packet(int pkttype, ...)
958{
39065bed 959 va_list ap1, ap2;
960 va_start(ap1, pkttype);
961 va_start(ap2, pkttype);
962 construct_packet(pkttype, ap1, ap2);
fb09bf1c 963 s_wrpkt();
964}
965
32874aea 966static void defer_packet(int pkttype, ...)
967{
39065bed 968 va_list ap1, ap2;
969 va_start(ap1, pkttype);
970 va_start(ap2, pkttype);
971 construct_packet(pkttype, ap1, ap2);
972 s_wrpkt_defer();
973}
974
32874aea 975static int ssh_versioncmp(char *a, char *b)
976{
9697bfd2 977 char *ae, *be;
978 unsigned long av, bv;
979
43aa02a7 980 av = strtoul(a, &ae, 10);
981 bv = strtoul(b, &be, 10);
32874aea 982 if (av != bv)
983 return (av < bv ? -1 : +1);
984 if (*ae == '.')
985 ae++;
986 if (*be == '.')
987 be++;
43aa02a7 988 av = strtoul(ae, &ae, 10);
989 bv = strtoul(be, &be, 10);
32874aea 990 if (av != bv)
991 return (av < bv ? -1 : +1);
9697bfd2 992 return 0;
993}
994
e5574168 995
996/*
a92dd380 997 * Utility routines for putting an SSH-protocol `string' and
998 * `uint32' into a SHA state.
e5574168 999 */
1000#include <stdio.h>
32874aea 1001static void sha_string(SHA_State * s, void *str, int len)
1002{
e5574168 1003 unsigned char lenblk[4];
e5574168 1004 PUT_32BIT(lenblk, len);
e5574168 1005 SHA_Bytes(s, lenblk, 4);
e5574168 1006 SHA_Bytes(s, str, len);
1007}
1008
32874aea 1009static void sha_uint32(SHA_State * s, unsigned i)
1010{
a92dd380 1011 unsigned char intblk[4];
1012 PUT_32BIT(intblk, i);
1013 SHA_Bytes(s, intblk, 4);
1014}
1015
7cca0d81 1016/*
1017 * SSH2 packet construction functions.
1018 */
32874aea 1019static void ssh2_pkt_ensure(int length)
1020{
783415f8 1021 if (pktout.maxlen < length) {
32874aea 1022 pktout.maxlen = length + 256;
1023 pktout.data =
1024 (pktout.data ==
1025 NULL ? smalloc(pktout.maxlen +
1026 APIEXTRA) : srealloc(pktout.data,
1027 pktout.maxlen +
1028 APIEXTRA));
1029 if (!pktout.data)
1030 fatalbox("Out of memory");
7cca0d81 1031 }
783415f8 1032}
32874aea 1033static void ssh2_pkt_adddata(void *data, int len)
1034{
783415f8 1035 pktout.length += len;
1036 ssh2_pkt_ensure(pktout.length);
32874aea 1037 memcpy(pktout.data + pktout.length - len, data, len);
7cca0d81 1038}
32874aea 1039static void ssh2_pkt_addbyte(unsigned char byte)
1040{
7cca0d81 1041 ssh2_pkt_adddata(&byte, 1);
1042}
32874aea 1043static void ssh2_pkt_init(int pkt_type)
1044{
7cca0d81 1045 pktout.length = 5;
32874aea 1046 ssh2_pkt_addbyte((unsigned char) pkt_type);
7cca0d81 1047}
32874aea 1048static void ssh2_pkt_addbool(unsigned char value)
1049{
7cca0d81 1050 ssh2_pkt_adddata(&value, 1);
1051}
32874aea 1052static void ssh2_pkt_adduint32(unsigned long value)
1053{
7cca0d81 1054 unsigned char x[4];
1055 PUT_32BIT(x, value);
1056 ssh2_pkt_adddata(x, 4);
1057}
32874aea 1058static void ssh2_pkt_addstring_start(void)
1059{
7cca0d81 1060 ssh2_pkt_adduint32(0);
1061 pktout.savedpos = pktout.length;
1062}
32874aea 1063static void ssh2_pkt_addstring_str(char *data)
1064{
7cca0d81 1065 ssh2_pkt_adddata(data, strlen(data));
1066 PUT_32BIT(pktout.data + pktout.savedpos - 4,
32874aea 1067 pktout.length - pktout.savedpos);
7cca0d81 1068}
32874aea 1069static void ssh2_pkt_addstring_data(char *data, int len)
1070{
7cca0d81 1071 ssh2_pkt_adddata(data, len);
1072 PUT_32BIT(pktout.data + pktout.savedpos - 4,
32874aea 1073 pktout.length - pktout.savedpos);
7cca0d81 1074}
32874aea 1075static void ssh2_pkt_addstring(char *data)
1076{
7cca0d81 1077 ssh2_pkt_addstring_start();
1078 ssh2_pkt_addstring_str(data);
1079}
32874aea 1080static char *ssh2_mpint_fmt(Bignum b, int *len)
1081{
7cca0d81 1082 unsigned char *p;
32874aea 1083 int i, n = (bignum_bitcount(b) + 7) / 8;
3709bfe9 1084 p = smalloc(n + 1);
7cca0d81 1085 if (!p)
32874aea 1086 fatalbox("out of memory");
7cca0d81 1087 p[0] = 0;
3709bfe9 1088 for (i = 1; i <= n; i++)
32874aea 1089 p[i] = bignum_byte(b, n - i);
7cca0d81 1090 i = 0;
32874aea 1091 while (i <= n && p[i] == 0 && (p[i + 1] & 0x80) == 0)
1092 i++;
1093 memmove(p, p + i, n + 1 - i);
1094 *len = n + 1 - i;
7cca0d81 1095 return p;
1096}
32874aea 1097static void ssh2_pkt_addmp(Bignum b)
1098{
7cca0d81 1099 unsigned char *p;
1100 int len;
1101 p = ssh2_mpint_fmt(b, &len);
1102 ssh2_pkt_addstring_start();
1103 ssh2_pkt_addstring_data(p, len);
dcbde236 1104 sfree(p);
7cca0d81 1105}
b185170a 1106
1107/*
1108 * Construct an SSH2 final-form packet: compress it, encrypt it,
1109 * put the MAC on it. Final packet, ready to be sent, is stored in
1110 * pktout.data. Total length is returned.
1111 */
32874aea 1112static int ssh2_pkt_construct(void)
1113{
7cca0d81 1114 int cipherblk, maclen, padding, i;
1115 static unsigned long outgoing_sequence = 0;
1116
1117 /*
4ba9b64b 1118 * Compress packet payload.
1119 */
765c4200 1120#ifdef DUMP_PACKETS
1121 debug(("Pre-compression payload:\n"));
32874aea 1122 dmemdump(pktout.data + 5, pktout.length - 5);
4ba9b64b 1123#endif
1124 {
1125 unsigned char *newpayload;
1126 int newlen;
32874aea 1127 if (cscomp && cscomp->compress(pktout.data + 5, pktout.length - 5,
4ba9b64b 1128 &newpayload, &newlen)) {
1129 pktout.length = 5;
1130 ssh2_pkt_adddata(newpayload, newlen);
dcbde236 1131 sfree(newpayload);
4ba9b64b 1132 }
1133 }
1134
1135 /*
7cca0d81 1136 * Add padding. At least four bytes, and must also bring total
1137 * length (minus MAC) up to a multiple of the block size.
1138 */
32874aea 1139 cipherblk = cscipher ? cscipher->blksize : 8; /* block size */
1140 cipherblk = cipherblk < 8 ? 8 : cipherblk; /* or 8 if blksize < 8 */
7cca0d81 1141 padding = 4;
32874aea 1142 padding +=
1143 (cipherblk - (pktout.length + padding) % cipherblk) % cipherblk;
783415f8 1144 maclen = csmac ? csmac->len : 0;
1145 ssh2_pkt_ensure(pktout.length + padding + maclen);
7cca0d81 1146 pktout.data[4] = padding;
1147 for (i = 0; i < padding; i++)
32874aea 1148 pktout.data[pktout.length + i] = random_byte();
7cca0d81 1149 PUT_32BIT(pktout.data, pktout.length + padding - 4);
1150 if (csmac)
32874aea 1151 csmac->generate(pktout.data, pktout.length + padding,
1152 outgoing_sequence);
1153 outgoing_sequence++; /* whether or not we MACed */
7cca0d81 1154
765c4200 1155#ifdef DUMP_PACKETS
32874aea 1156 debug(("Sending packet len=%d\n", pktout.length + padding));
1157 dmemdump(pktout.data, pktout.length + padding);
7cca0d81 1158#endif
1159
1160 if (cscipher)
32874aea 1161 cscipher->encrypt(pktout.data, pktout.length + padding);
7cca0d81 1162
b185170a 1163 /* Ready-to-send packet starts at pktout.data. We return length. */
1164 return pktout.length + padding + maclen;
1165}
1166
1167/*
1168 * Construct and send an SSH2 packet immediately.
1169 */
32874aea 1170static void ssh2_pkt_send(void)
1171{
b185170a 1172 int len = ssh2_pkt_construct();
1173 sk_write(s, pktout.data, len);
1174}
1175
1176/*
1177 * Construct an SSH2 packet and add it to a deferred data block.
1178 * Useful for sending multiple packets in a single sk_write() call,
1179 * to prevent a traffic-analysing listener from being able to work
1180 * out the length of any particular packet (such as the password
1181 * packet).
1182 *
1183 * Note that because SSH2 sequence-numbers its packets, this can
1184 * NOT be used as an m4-style `defer' allowing packets to be
1185 * constructed in one order and sent in another.
1186 */
32874aea 1187static void ssh2_pkt_defer(void)
1188{
b185170a 1189 int len = ssh2_pkt_construct();
1190 if (deferred_len + len > deferred_size) {
32874aea 1191 deferred_size = deferred_len + len + 128;
1192 deferred_send_data = srealloc(deferred_send_data, deferred_size);
b185170a 1193 }
32874aea 1194 memcpy(deferred_send_data + deferred_len, pktout.data, len);
b185170a 1195 deferred_len += len;
1196}
1197
1198/*
1199 * Send the whole deferred data block constructed by
39065bed 1200 * ssh2_pkt_defer() or SSH1's defer_packet().
b185170a 1201 */
32874aea 1202static void ssh_pkt_defersend(void)
1203{
b185170a 1204 sk_write(s, deferred_send_data, deferred_len);
1205 deferred_len = deferred_size = 0;
1206 sfree(deferred_send_data);
1207 deferred_send_data = NULL;
7cca0d81 1208}
1209
1210#if 0
32874aea 1211void bndebug(char *string, Bignum b)
1212{
7cca0d81 1213 unsigned char *p;
1214 int i, len;
1215 p = ssh2_mpint_fmt(b, &len);
1216 debug(("%s", string));
1217 for (i = 0; i < len; i++)
32874aea 1218 debug((" %02x", p[i]));
765c4200 1219 debug(("\n"));
dcbde236 1220 sfree(p);
7cca0d81 1221}
1222#endif
1223
32874aea 1224static void sha_mpint(SHA_State * s, Bignum b)
1225{
7cca0d81 1226 unsigned char *p;
1227 int len;
1228 p = ssh2_mpint_fmt(b, &len);
1229 sha_string(s, p, len);
dcbde236 1230 sfree(p);
7cca0d81 1231}
1232
1233/*
1234 * SSH2 packet decode functions.
1235 */
32874aea 1236static unsigned long ssh2_pkt_getuint32(void)
1237{
7cca0d81 1238 unsigned long value;
1239 if (pktin.length - pktin.savedpos < 4)
32874aea 1240 return 0; /* arrgh, no way to decline (FIXME?) */
1241 value = GET_32BIT(pktin.data + pktin.savedpos);
7cca0d81 1242 pktin.savedpos += 4;
1243 return value;
1244}
32874aea 1245static int ssh2_pkt_getbool(void)
1246{
65a22376 1247 unsigned long value;
1248 if (pktin.length - pktin.savedpos < 1)
32874aea 1249 return 0; /* arrgh, no way to decline (FIXME?) */
65a22376 1250 value = pktin.data[pktin.savedpos] != 0;
1251 pktin.savedpos++;
1252 return value;
1253}
32874aea 1254static void ssh2_pkt_getstring(char **p, int *length)
1255{
7cca0d81 1256 *p = NULL;
1257 if (pktin.length - pktin.savedpos < 4)
32874aea 1258 return;
1259 *length = GET_32BIT(pktin.data + pktin.savedpos);
7cca0d81 1260 pktin.savedpos += 4;
1261 if (pktin.length - pktin.savedpos < *length)
32874aea 1262 return;
1263 *p = pktin.data + pktin.savedpos;
7cca0d81 1264 pktin.savedpos += *length;
1265}
32874aea 1266static Bignum ssh2_pkt_getmp(void)
1267{
7cca0d81 1268 char *p;
3709bfe9 1269 int length;
7cca0d81 1270 Bignum b;
1271
1272 ssh2_pkt_getstring(&p, &length);
1273 if (!p)
32874aea 1274 return NULL;
8d5de777 1275 if (p[0] & 0x80) {
32874aea 1276 bombout(("internal error: Can't handle negative mpints"));
1277 return NULL;
8d5de777 1278 }
3709bfe9 1279 b = bignum_from_bytes(p, length);
7cca0d81 1280 return b;
1281}
1282
7d503c31 1283/*
1284 * Examine the remote side's version string and compare it against
1285 * a list of known buggy implementations.
1286 */
32874aea 1287static void ssh_detect_bugs(char *vstring)
1288{
1289 char *imp; /* pointer to implementation part */
7d503c31 1290 imp = vstring;
1291 imp += strcspn(imp, "-");
32874aea 1292 if (*imp)
1293 imp++;
7d503c31 1294 imp += strcspn(imp, "-");
32874aea 1295 if (*imp)
1296 imp++;
7d503c31 1297
1298 ssh_remote_bugs = 0;
1299
1300 if (!strcmp(imp, "1.2.18") || !strcmp(imp, "1.2.19") ||
32874aea 1301 !strcmp(imp, "1.2.20") || !strcmp(imp, "1.2.21") ||
1302 !strcmp(imp, "1.2.22")) {
1303 /*
1304 * These versions don't support SSH1_MSG_IGNORE, so we have
1305 * to use a different defence against password length
1306 * sniffing.
1307 */
1308 ssh_remote_bugs |= BUG_CHOKES_ON_SSH1_IGNORE;
1309 logevent("We believe remote version has SSH1 ignore bug");
7d503c31 1310 }
1311
1312 if (!strncmp(imp, "2.1.0", 5) || !strncmp(imp, "2.0.", 4) ||
32874aea 1313 !strncmp(imp, "2.2.0", 5) || !strncmp(imp, "2.3.0", 5) ||
1314 !strncmp(imp, "2.1 ", 4)) {
1315 /*
1316 * These versions have the HMAC bug.
1317 */
1318 ssh_remote_bugs |= BUG_SSH2_HMAC;
1319 logevent("We believe remote version has SSH2 HMAC bug");
7d503c31 1320 }
1321}
1322
32874aea 1323static int do_ssh_init(unsigned char c)
1324{
2d466ffd 1325 static int vslen;
8df7a775 1326 static char version[10];
50526e47 1327 static char *vstring;
1328 static int vstrsize;
1329 static char *vlog;
8df7a775 1330 static int i;
374330e2 1331
8df7a775 1332 crBegin;
1333
1334 /* Search for the string "SSH-" in the input. */
374330e2 1335 i = 0;
8df7a775 1336 while (1) {
1337 static const int transS[] = { 1, 2, 2, 1 };
1338 static const int transH[] = { 0, 0, 3, 0 };
1339 static const int transminus[] = { 0, 0, 0, -1 };
32874aea 1340 if (c == 'S')
1341 i = transS[i];
1342 else if (c == 'H')
1343 i = transH[i];
1344 else if (c == '-')
1345 i = transminus[i];
1346 else
1347 i = 0;
8df7a775 1348 if (i < 0)
1349 break;
1350 crReturn(1); /* get another character */
374330e2 1351 }
8df7a775 1352
50526e47 1353 vstring = smalloc(16);
1354 vstrsize = 16;
c5e9c988 1355 strcpy(vstring, "SSH-");
50526e47 1356 vslen = 4;
374330e2 1357 i = 0;
1358 while (1) {
8df7a775 1359 crReturn(1); /* get another char */
32874aea 1360 if (vslen >= vstrsize - 1) {
1361 vstrsize += 16;
1362 vstring = srealloc(vstring, vstrsize);
1363 }
1364 vstring[vslen++] = c;
374330e2 1365 if (i >= 0) {
1366 if (c == '-') {
1367 version[i] = '\0';
1368 i = -1;
32874aea 1369 } else if (i < sizeof(version) - 1)
374330e2 1370 version[i++] = c;
32874aea 1371 } else if (c == '\n')
374330e2 1372 break;
1373 }
1374
db7d555c 1375 ssh_agentfwd_enabled = FALSE;
960e736a 1376 rdpkt2_state.incoming_sequence = 0;
1377
50526e47 1378 vstring[vslen] = 0;
9275ca8a 1379 vlog = smalloc(20 + vslen);
c5e9c988 1380 sprintf(vlog, "Server version: %s", vstring);
7d503c31 1381 ssh_detect_bugs(vstring);
c5e9c988 1382 vlog[strcspn(vlog, "\r\n")] = '\0';
1383 logevent(vlog);
9275ca8a 1384 sfree(vlog);
c5e9c988 1385
adf799dd 1386 /*
1387 * Server version "1.99" means we can choose whether we use v1
1388 * or v2 protocol. Choice is based on cfg.sshprot.
1389 */
1390 if (ssh_versioncmp(version, cfg.sshprot == 1 ? "2.0" : "1.99") >= 0) {
32874aea 1391 /*
1392 * This is a v2 server. Begin v2 protocol.
1393 */
1394 char verstring[80], vlog[100];
1395 sprintf(verstring, "SSH-2.0-%s", sshver);
1396 SHA_Init(&exhashbase);
1397 /*
1398 * Hash our version string and their version string.
1399 */
1400 sha_string(&exhashbase, verstring, strlen(verstring));
1401 sha_string(&exhashbase, vstring, strcspn(vstring, "\r\n"));
1402 sprintf(vlog, "We claim version: %s", verstring);
1403 logevent(vlog);
1404 strcat(verstring, "\n");
1405 logevent("Using SSH protocol version 2");
1406 sk_write(s, verstring, strlen(verstring));
1407 ssh_protocol = ssh2_protocol;
1408 ssh_version = 2;
1409 s_rdpkt = ssh2_rdpkt;
e5574168 1410 } else {
32874aea 1411 /*
1412 * This is a v1 server. Begin v1 protocol.
1413 */
1414 char verstring[80], vlog[100];
1415 sprintf(verstring, "SSH-%s-%s",
1416 (ssh_versioncmp(version, "1.5") <= 0 ? version : "1.5"),
1417 sshver);
1418 sprintf(vlog, "We claim version: %s", verstring);
1419 logevent(vlog);
1420 strcat(verstring, "\n");
1421 logevent("Using SSH protocol version 1");
1422 sk_write(s, verstring, strlen(verstring));
1423 ssh_protocol = ssh1_protocol;
1424 ssh_version = 1;
1425 s_rdpkt = ssh1_rdpkt;
e5574168 1426 }
3687d221 1427 ssh_state = SSH_STATE_BEFORE_SIZE;
8df7a775 1428
50526e47 1429 sfree(vstring);
50526e47 1430
8df7a775 1431 crFinish(0);
1432}
1433
1434static void ssh_gotdata(unsigned char *data, int datalen)
1435{
1436 crBegin;
1437
1438 /*
1439 * To begin with, feed the characters one by one to the
1440 * protocol initialisation / selection function do_ssh_init().
1441 * When that returns 0, we're done with the initial greeting
1442 * exchange and can move on to packet discipline.
1443 */
1444 while (1) {
1445 int ret;
1446 if (datalen == 0)
1447 crReturnV; /* more data please */
1448 ret = do_ssh_init(*data);
32874aea 1449 data++;
1450 datalen--;
8df7a775 1451 if (ret == 0)
1452 break;
1453 }
1454
1455 /*
1456 * We emerge from that loop when the initial negotiation is
1457 * over and we have selected an s_rdpkt function. Now pass
1458 * everything to s_rdpkt, and then pass the resulting packets
1459 * to the proper protocol handler.
1460 */
1461 if (datalen == 0)
1462 crReturnV;
1463 while (1) {
1464 while (datalen > 0) {
32874aea 1465 if (s_rdpkt(&data, &datalen) == 0) {
8df7a775 1466 ssh_protocol(NULL, 0, 1);
1467 if (ssh_state == SSH_STATE_CLOSED) {
1468 return;
1469 }
1470 }
1471 }
1472 crReturnV;
1473 }
1474 crFinishV;
1475}
1476
32874aea 1477static int ssh_closing(Plug plug, char *error_msg, int error_code,
1478 int calling_back)
1479{
7e78000d 1480 ssh_state = SSH_STATE_CLOSED;
1481 sk_close(s);
1482 s = NULL;
1483 if (error_msg) {
32874aea 1484 /* A socket error has occurred. */
1485 connection_fatal(error_msg);
7e78000d 1486 } else {
1487 /* Otherwise, the remote side closed the connection normally. */
8df7a775 1488 }
7e78000d 1489 return 0;
1490}
1491
32874aea 1492static int ssh_receive(Plug plug, int urgent, char *data, int len)
1493{
1494 ssh_gotdata(data, len);
3257deae 1495 if (ssh_state == SSH_STATE_CLOSED) {
32874aea 1496 if (s) {
1497 sk_close(s);
1498 s = NULL;
1499 }
1500 return 0;
3257deae 1501 }
fef97f43 1502 return 1;
374330e2 1503}
1504
fb09bf1c 1505/*
8df7a775 1506 * Connect to specified host and port.
1507 * Returns an error message, or NULL on success.
6e1ebb76 1508 * Also places the canonical host name into `realhost'. It must be
1509 * freed by the caller.
8df7a775 1510 */
1511static char *connect_to_host(char *host, int port, char **realhost)
1512{
7e78000d 1513 static struct plug_function_table fn_table = {
1514 ssh_closing,
1515 ssh_receive
1516 }, *fn_table_ptr = &fn_table;
1517
8df7a775 1518 SockAddr addr;
1519 char *err;
1520#ifdef FWHACK
1521 char *FWhost;
1522 int FWport;
1523#endif
1524
32874aea 1525 savedhost = smalloc(1 + strlen(host));
8df7a775 1526 if (!savedhost)
1527 fatalbox("Out of memory");
1528 strcpy(savedhost, host);
1529
1530 if (port < 0)
1531 port = 22; /* default ssh port */
1532 savedport = port;
1533
1534#ifdef FWHACK
1535 FWhost = host;
1536 FWport = port;
1537 host = FWSTR;
1538 port = 23;
1539#endif
1540
1541 /*
1542 * Try to find host.
1543 */
1544 addr = sk_namelookup(host, realhost);
32874aea 1545 if ((err = sk_addr_error(addr)))
8df7a775 1546 return err;
1547
1548#ifdef FWHACK
6e1ebb76 1549 *realhost = strdup(FWhost);
8df7a775 1550#endif
1551
1552 /*
1553 * Open socket.
1554 */
7e78000d 1555 s = sk_new(addr, port, 0, 1, &fn_table_ptr);
32874aea 1556 if ((err = sk_socket_error(s)))
8df7a775 1557 return err;
1558
1559#ifdef FWHACK
1560 sk_write(s, "connect ", 8);
1561 sk_write(s, FWhost, strlen(FWhost));
1562 {
1563 char buf[20];
1564 sprintf(buf, " %d\n", FWport);
1565 sk_write(s, buf, strlen(buf));
1566 }
1567#endif
1568
1569 return NULL;
1570}
1571
1572/*
fb09bf1c 1573 * Handle the key exchange and user authentication phases.
1574 */
e5574168 1575static int do_ssh1_login(unsigned char *in, int inlen, int ispkt)
fb09bf1c 1576{
2d466ffd 1577 int i, j;
1578 static int len;
1579 static unsigned char *rsabuf, *keystr1, *keystr2;
374330e2 1580 unsigned char cookie[8];
1581 struct RSAKey servkey, hostkey;
1582 struct MD5Context md5c;
ccbfb941 1583 static unsigned long supported_ciphers_mask, supported_auths_mask;
7cca0d81 1584 static int tried_publickey;
1585 static unsigned char session_id[16];
2d466ffd 1586 static int cipher_type;
b585ec46 1587 static char username[100];
374330e2 1588
374330e2 1589 crBegin;
1590
32874aea 1591 if (!ispkt)
1592 crWaitUntil(ispkt);
374330e2 1593
8d5de777 1594 if (pktin.type != SSH1_SMSG_PUBLIC_KEY) {
1595 bombout(("Public key packet not received"));
32874aea 1596 crReturn(0);
8d5de777 1597 }
374330e2 1598
c5e9c988 1599 logevent("Received public keys");
374330e2 1600
c5e9c988 1601 memcpy(cookie, pktin.body, 8);
374330e2 1602
32874aea 1603 i = makekey(pktin.body + 8, &servkey, &keystr1, 0);
1604 j = makekey(pktin.body + 8 + i, &hostkey, &keystr2, 0);
374330e2 1605
c5e9c988 1606 /*
1c2a93c4 1607 * Log the host key fingerprint.
c5e9c988 1608 */
c5e9c988 1609 {
1610 char logmsg[80];
1c2a93c4 1611 logevent("Host key fingerprint is:");
c5e9c988 1612 strcpy(logmsg, " ");
32874aea 1613 hostkey.comment = NULL;
1614 rsa_fingerprint(logmsg + strlen(logmsg),
1615 sizeof(logmsg) - strlen(logmsg), &hostkey);
c5e9c988 1616 logevent(logmsg);
1617 }
1618
32874aea 1619 ssh1_remote_protoflags = GET_32BIT(pktin.body + 8 + i + j);
1620 supported_ciphers_mask = GET_32BIT(pktin.body + 12 + i + j);
1621 supported_auths_mask = GET_32BIT(pktin.body + 16 + i + j);
bea1ef5f 1622
32874aea 1623 ssh1_local_protoflags =
1624 ssh1_remote_protoflags & SSH1_PROTOFLAGS_SUPPORTED;
b96dc54c 1625 ssh1_local_protoflags |= SSH1_PROTOFLAG_SCREEN_NUMBER;
1626
c5e9c988 1627 MD5Init(&md5c);
374330e2 1628 MD5Update(&md5c, keystr2, hostkey.bytes);
1629 MD5Update(&md5c, keystr1, servkey.bytes);
1630 MD5Update(&md5c, pktin.body, 8);
374330e2 1631 MD5Final(session_id, &md5c);
1632
32874aea 1633 for (i = 0; i < 32; i++)
374330e2 1634 session_key[i] = random_byte();
1635
1636 len = (hostkey.bytes > servkey.bytes ? hostkey.bytes : servkey.bytes);
1637
dcbde236 1638 rsabuf = smalloc(len);
374330e2 1639 if (!rsabuf)
1640 fatalbox("Out of memory");
1641
89ee5268 1642 /*
1643 * Verify the host key.
1644 */
1645 {
32874aea 1646 /*
1647 * First format the key into a string.
1648 */
1649 int len = rsastr_len(&hostkey);
1650 char fingerprint[100];
1651 char *keystr = smalloc(len);
1652 if (!keystr)
1653 fatalbox("Out of memory");
1654 rsastr_fmt(keystr, &hostkey);
1655 rsa_fingerprint(fingerprint, sizeof(fingerprint), &hostkey);
1656 verify_ssh_host_key(savedhost, savedport, "rsa", keystr,
1657 fingerprint);
1658 sfree(keystr);
1659 }
1660
1661 for (i = 0; i < 32; i++) {
374330e2 1662 rsabuf[i] = session_key[i];
1663 if (i < 16)
1664 rsabuf[i] ^= session_id[i];
1665 }
1666
1667 if (hostkey.bytes > servkey.bytes) {
1668 rsaencrypt(rsabuf, 32, &servkey);
1669 rsaencrypt(rsabuf, servkey.bytes, &hostkey);
1670 } else {
1671 rsaencrypt(rsabuf, 32, &hostkey);
1672 rsaencrypt(rsabuf, hostkey.bytes, &servkey);
1673 }
1674
c5e9c988 1675 logevent("Encrypted session key");
1676
0a3f1d48 1677 switch (cfg.cipher) {
32874aea 1678 case CIPHER_BLOWFISH:
1679 cipher_type = SSH_CIPHER_BLOWFISH;
1680 break;
1681 case CIPHER_DES:
1682 cipher_type = SSH_CIPHER_DES;
1683 break;
1684 case CIPHER_3DES:
1685 cipher_type = SSH_CIPHER_3DES;
1686 break;
0a3f1d48 1687 case CIPHER_AES:
32874aea 1688 c_write_str("AES not supported in SSH1, falling back to 3DES\r\n");
1689 cipher_type = SSH_CIPHER_3DES;
1690 break;
0a3f1d48 1691 }
bea1ef5f 1692 if ((supported_ciphers_mask & (1 << cipher_type)) == 0) {
32874aea 1693 c_write_str
1694 ("Selected cipher not supported, falling back to 3DES\r\n");
bea1ef5f 1695 cipher_type = SSH_CIPHER_3DES;
a99a05c0 1696 if ((supported_ciphers_mask & (1 << cipher_type)) == 0) {
1697 bombout(("Server violates SSH 1 protocol by "
1698 "not supporting 3DES encryption"));
1699 crReturn(0);
1700 }
bea1ef5f 1701 }
c5e9c988 1702 switch (cipher_type) {
32874aea 1703 case SSH_CIPHER_3DES:
1704 logevent("Using 3DES encryption");
1705 break;
1706 case SSH_CIPHER_DES:
1707 logevent("Using single-DES encryption");
1708 break;
1709 case SSH_CIPHER_BLOWFISH:
1710 logevent("Using Blowfish encryption");
1711 break;
c5e9c988 1712 }
bea1ef5f 1713
e5574168 1714 send_packet(SSH1_CMSG_SESSION_KEY,
32874aea 1715 PKT_CHAR, cipher_type,
1716 PKT_DATA, cookie, 8,
1717 PKT_CHAR, (len * 8) >> 8, PKT_CHAR, (len * 8) & 0xFF,
1718 PKT_DATA, rsabuf, len,
1719 PKT_INT, ssh1_local_protoflags, PKT_END);
fb09bf1c 1720
c5e9c988 1721 logevent("Trying to enable encryption...");
374330e2 1722
dcbde236 1723 sfree(rsabuf);
374330e2 1724
5e8358ad 1725 cipher = cipher_type == SSH_CIPHER_BLOWFISH ? &ssh_blowfish_ssh1 :
32874aea 1726 cipher_type == SSH_CIPHER_DES ? &ssh_des : &ssh_3des;
374330e2 1727 cipher->sesskey(session_key);
1728
fb09bf1c 1729 crWaitUntil(ispkt);
374330e2 1730
8d5de777 1731 if (pktin.type != SSH1_SMSG_SUCCESS) {
1732 bombout(("Encryption not successfully enabled"));
32874aea 1733 crReturn(0);
8d5de777 1734 }
374330e2 1735
c5e9c988 1736 logevent("Successfully started encryption");
1737
374330e2 1738 fflush(stdout);
1739 {
374330e2 1740 static int pos = 0;
1741 static char c;
67779be7 1742 if ((flags & FLAG_INTERACTIVE) && !*cfg.username) {
32874aea 1743 if (ssh_get_line) {
1744 if (!ssh_get_line("login as: ",
1745 username, sizeof(username), FALSE)) {
1746 /*
1747 * get_line failed to get a username.
1748 * Terminate.
1749 */
1750 logevent("No username provided. Abandoning session.");
1751 ssh_state = SSH_STATE_CLOSED;
1752 crReturn(1);
1753 }
1754 } else {
1755 c_write_str("login as: ");
1756 ssh_send_ok = 1;
1757 while (pos >= 0) {
1758 crWaitUntil(!ispkt);
1759 while (inlen--)
1760 switch (c = *in++) {
1761 case 10:
1762 case 13:
1763 username[pos] = 0;
1764 pos = -1;
1765 break;
1766 case 8:
1767 case 127:
1768 if (pos > 0) {
1769 c_write_str("\b \b");
1770 pos--;
1771 }
1772 break;
1773 case 21:
1774 case 27:
1775 while (pos > 0) {
1776 c_write_str("\b \b");
1777 pos--;
1778 }
1779 break;
1780 case 3:
1781 case 4:
1782 random_save_seed();
1783 exit(0);
1784 break;
1785 default:
1786 if (((c >= ' ' && c <= '~') ||
51b2fb65 1787 ((unsigned char) c >= 160))
1788 && pos < sizeof(username)-1) {
32874aea 1789 username[pos++] = c;
1790 c_write(&c, 1);
1791 }
1792 break;
1793 }
1794 }
1795 c_write_str("\r\n");
1796 username[strcspn(username, "\n\r")] = '\0';
1797 }
1798 } else {
374330e2 1799 strncpy(username, cfg.username, 99);
1800 username[99] = '\0';
374330e2 1801 }
fb09bf1c 1802
e5574168 1803 send_packet(SSH1_CMSG_USER, PKT_STR, username, PKT_END);
c5e9c988 1804 {
32874aea 1805 char userlog[22 + sizeof(username)];
c5e9c988 1806 sprintf(userlog, "Sent username \"%s\"", username);
1807 logevent(userlog);
32874aea 1808 if (flags & FLAG_INTERACTIVE &&
1809 (!((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)))) {
3c8e959b 1810 strcat(userlog, "\r\n");
32874aea 1811 c_write_str(userlog);
3c8e959b 1812 }
c5e9c988 1813 }
374330e2 1814 }
1815
fb09bf1c 1816 crWaitUntil(ispkt);
374330e2 1817
7cca0d81 1818 tried_publickey = 0;
1819
e5574168 1820 while (pktin.type == SSH1_SMSG_FAILURE) {
374330e2 1821 static char password[100];
a52f067e 1822 static char prompt[200];
374330e2 1823 static int pos;
1824 static char c;
32874aea 1825 static int pwpkt_type;
1826 /*
1827 * Show password prompt, having first obtained it via a TIS
1828 * or CryptoCard exchange if we're doing TIS or CryptoCard
1829 * authentication.
1830 */
1831 pwpkt_type = SSH1_CMSG_AUTH_PASSWORD;
1832 if (agent_exists()) {
1833 /*
1834 * Attempt RSA authentication using Pageant.
1835 */
1836 static unsigned char request[5], *response, *p;
1837 static int responselen;
1838 static int i, nkeys;
1839 static int authed = FALSE;
1840 void *r;
1841
1842 logevent("Pageant is running. Requesting keys.");
1843
1844 /* Request the keys held by the agent. */
1845 PUT_32BIT(request, 1);
1846 request[4] = SSH1_AGENTC_REQUEST_RSA_IDENTITIES;
1847 agent_query(request, 5, &r, &responselen);
1848 response = (unsigned char *) r;
1849 if (response && responselen >= 5 &&
1850 response[4] == SSH1_AGENT_RSA_IDENTITIES_ANSWER) {
1851 p = response + 5;
1852 nkeys = GET_32BIT(p);
1853 p += 4;
1854 {
1855 char buf[64];
1856 sprintf(buf, "Pageant has %d SSH1 keys", nkeys);
1857 logevent(buf);
1858 }
1859 for (i = 0; i < nkeys; i++) {
1860 static struct RSAKey key;
1861 static Bignum challenge;
1862 static char *commentp;
1863 static int commentlen;
1864
1865 {
1866 char buf[64];
1867 sprintf(buf, "Trying Pageant key #%d", i);
1868 logevent(buf);
1869 }
1870 p += 4;
1871 p += ssh1_read_bignum(p, &key.exponent);
1872 p += ssh1_read_bignum(p, &key.modulus);
1873 commentlen = GET_32BIT(p);
1874 p += 4;
1875 commentp = p;
1876 p += commentlen;
1877 send_packet(SSH1_CMSG_AUTH_RSA,
1878 PKT_BIGNUM, key.modulus, PKT_END);
1879 crWaitUntil(ispkt);
1880 if (pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
1881 logevent("Key refused");
1882 continue;
1883 }
1884 logevent("Received RSA challenge");
1885 ssh1_read_bignum(pktin.body, &challenge);
1886 {
1887 char *agentreq, *q, *ret;
2d466ffd 1888 void *vret;
32874aea 1889 int len, retlen;
1890 len = 1 + 4; /* message type, bit count */
1891 len += ssh1_bignum_length(key.exponent);
1892 len += ssh1_bignum_length(key.modulus);
1893 len += ssh1_bignum_length(challenge);
1894 len += 16; /* session id */
1895 len += 4; /* response format */
1896 agentreq = smalloc(4 + len);
1897 PUT_32BIT(agentreq, len);
1898 q = agentreq + 4;
1899 *q++ = SSH1_AGENTC_RSA_CHALLENGE;
1900 PUT_32BIT(q, bignum_bitcount(key.modulus));
1901 q += 4;
1902 q += ssh1_write_bignum(q, key.exponent);
1903 q += ssh1_write_bignum(q, key.modulus);
1904 q += ssh1_write_bignum(q, challenge);
1905 memcpy(q, session_id, 16);
1906 q += 16;
1907 PUT_32BIT(q, 1); /* response format */
2d466ffd 1908 agent_query(agentreq, len + 4, &vret, &retlen);
1909 ret = vret;
32874aea 1910 sfree(agentreq);
1911 if (ret) {
1912 if (ret[4] == SSH1_AGENT_RSA_RESPONSE) {
1913 logevent("Sending Pageant's response");
1914 send_packet(SSH1_CMSG_AUTH_RSA_RESPONSE,
1915 PKT_DATA, ret + 5, 16,
1916 PKT_END);
1917 sfree(ret);
1918 crWaitUntil(ispkt);
1919 if (pktin.type == SSH1_SMSG_SUCCESS) {
1920 logevent
1921 ("Pageant's response accepted");
1922 if (flags & FLAG_VERBOSE) {
1923 c_write_str
1924 ("Authenticated using RSA key \"");
1925 c_write(commentp, commentlen);
1926 c_write_str("\" from agent\r\n");
1927 }
1928 authed = TRUE;
1929 } else
1930 logevent
1931 ("Pageant's response not accepted");
1932 } else {
1933 logevent
1934 ("Pageant failed to answer challenge");
1935 sfree(ret);
1936 }
1937 } else {
1938 logevent("No reply received from Pageant");
1939 }
1940 }
1941 freebn(key.exponent);
1942 freebn(key.modulus);
1943 freebn(challenge);
1944 if (authed)
1945 break;
1946 }
1947 }
1948 if (authed)
1949 break;
1950 }
1951 if (*cfg.keyfile && !tried_publickey)
1952 pwpkt_type = SSH1_CMSG_AUTH_RSA;
1953
1954 if (pktin.type == SSH1_SMSG_FAILURE &&
1955 cfg.try_tis_auth &&
1956 (supported_auths_mask & (1 << SSH1_AUTH_TIS))) {
1957 pwpkt_type = SSH1_CMSG_AUTH_TIS_RESPONSE;
1958 logevent("Requested TIS authentication");
1959 send_packet(SSH1_CMSG_AUTH_TIS, PKT_END);
1960 crWaitUntil(ispkt);
1961 if (pktin.type != SSH1_SMSG_AUTH_TIS_CHALLENGE) {
1962 logevent("TIS authentication declined");
1963 if (flags & FLAG_INTERACTIVE)
1964 c_write_str("TIS authentication refused.\r\n");
1965 } else {
1966 int challengelen = ((pktin.body[0] << 24) |
1967 (pktin.body[1] << 16) |
1968 (pktin.body[2] << 8) |
1969 (pktin.body[3]));
1970 logevent("Received TIS challenge");
1971 if (challengelen > sizeof(prompt) - 1)
1972 challengelen = sizeof(prompt) - 1; /* prevent overrun */
1973 memcpy(prompt, pktin.body + 4, challengelen);
1974 prompt[challengelen] = '\0';
1975 }
1976 }
1977 if (pktin.type == SSH1_SMSG_FAILURE &&
1978 cfg.try_tis_auth &&
1979 (supported_auths_mask & (1 << SSH1_AUTH_CCARD))) {
1980 pwpkt_type = SSH1_CMSG_AUTH_CCARD_RESPONSE;
1981 logevent("Requested CryptoCard authentication");
1982 send_packet(SSH1_CMSG_AUTH_CCARD, PKT_END);
1983 crWaitUntil(ispkt);
1984 if (pktin.type != SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
1985 logevent("CryptoCard authentication declined");
1986 c_write_str("CryptoCard authentication refused.\r\n");
1987 } else {
1988 int challengelen = ((pktin.body[0] << 24) |
1989 (pktin.body[1] << 16) |
1990 (pktin.body[2] << 8) |
1991 (pktin.body[3]));
1992 logevent("Received CryptoCard challenge");
1993 if (challengelen > sizeof(prompt) - 1)
1994 challengelen = sizeof(prompt) - 1; /* prevent overrun */
1995 memcpy(prompt, pktin.body + 4, challengelen);
1996 strncpy(prompt + challengelen, "\r\nResponse : ",
1997 sizeof(prompt) - challengelen);
1998 prompt[sizeof(prompt) - 1] = '\0';
1999 }
2000 }
2001 if (pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
2002 sprintf(prompt, "%.90s@%.90s's password: ",
2003 username, savedhost);
2004 }
2005 if (pwpkt_type == SSH1_CMSG_AUTH_RSA) {
2006 char *comment = NULL;
2007 if (flags & FLAG_VERBOSE)
2008 c_write_str("Trying public key authentication.\r\n");
2009 if (!rsakey_encrypted(cfg.keyfile, &comment)) {
2010 if (flags & FLAG_VERBOSE)
2011 c_write_str("No passphrase required.\r\n");
2012 goto tryauth;
2013 }
2014 sprintf(prompt, "Passphrase for key \"%.100s\": ", comment);
2015 sfree(comment);
2016 }
a52f067e 2017
fa17a66e 2018 if (ssh_get_line) {
2019 if (!ssh_get_line(prompt, password, sizeof(password), TRUE)) {
32874aea 2020 /*
2021 * get_line failed to get a password (for example
2022 * because one was supplied on the command line
2023 * which has already failed to work). Terminate.
2024 */
2bc6a386 2025 send_packet(SSH1_MSG_DISCONNECT,
2026 PKT_STR, "No more passwords available to try",
2027 PKT_END);
2028 connection_fatal("Unable to authenticate");
32874aea 2029 ssh_state = SSH_STATE_CLOSED;
2030 crReturn(1);
2031 }
fb09bf1c 2032 } else {
32874aea 2033 c_write_str(prompt);
2034 pos = 0;
2035 ssh_send_ok = 1;
2036 while (pos >= 0) {
2037 crWaitUntil(!ispkt);
2038 while (inlen--)
2039 switch (c = *in++) {
2040 case 10:
2041 case 13:
2042 password[pos] = 0;
2043 pos = -1;
2044 break;
2045 case 8:
2046 case 127:
2047 if (pos > 0)
2048 pos--;
2049 break;
2050 case 21:
2051 case 27:
2052 pos = 0;
2053 break;
2054 case 3:
2055 case 4:
2056 random_save_seed();
2057 exit(0);
2058 break;
2059 default:
51b2fb65 2060 if (pos < sizeof(password)-1)
32874aea 2061 password[pos++] = c;
2062 break;
2063 }
2064 }
2065 c_write_str("\r\n");
2066 }
2067
2068 tryauth:
7cca0d81 2069 if (pwpkt_type == SSH1_CMSG_AUTH_RSA) {
32874aea 2070 /*
2071 * Try public key authentication with the specified
2072 * key file.
2073 */
2074 static struct RSAKey pubkey;
2075 static Bignum challenge, response;
2076 static int i;
2077 static unsigned char buffer[32];
2078
2079 tried_publickey = 1;
2080 i = loadrsakey(cfg.keyfile, &pubkey, password);
2081 if (i == 0) {
2082 c_write_str("Couldn't load public key from ");
2083 c_write_str(cfg.keyfile);
2084 c_write_str(".\r\n");
2085 continue; /* go and try password */
2086 }
2087 if (i == -1) {
2088 c_write_str("Wrong passphrase.\r\n");
2089 tried_publickey = 0;
2090 continue; /* try again */
2091 }
2092
2093 /*
2094 * Send a public key attempt.
2095 */
2096 send_packet(SSH1_CMSG_AUTH_RSA,
2097 PKT_BIGNUM, pubkey.modulus, PKT_END);
2098
2099 crWaitUntil(ispkt);
2100 if (pktin.type == SSH1_SMSG_FAILURE) {
2101 c_write_str("Server refused our public key.\r\n");
2102 continue; /* go and try password */
2103 }
2104 if (pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
2105 bombout(("Bizarre response to offer of public key"));
2106 crReturn(0);
2107 }
2108 ssh1_read_bignum(pktin.body, &challenge);
2109 response = rsadecrypt(challenge, &pubkey);
2110 freebn(pubkey.private_exponent); /* burn the evidence */
2111
2112 for (i = 0; i < 32; i++) {
2113 buffer[i] = bignum_byte(response, 31 - i);
2114 }
2115
2116 MD5Init(&md5c);
2117 MD5Update(&md5c, buffer, 32);
2118 MD5Update(&md5c, session_id, 16);
2119 MD5Final(buffer, &md5c);
2120
2121 send_packet(SSH1_CMSG_AUTH_RSA_RESPONSE,
2122 PKT_DATA, buffer, 16, PKT_END);
2123
2124 crWaitUntil(ispkt);
2125 if (pktin.type == SSH1_SMSG_FAILURE) {
2126 if (flags & FLAG_VERBOSE)
2127 c_write_str
2128 ("Failed to authenticate with our public key.\r\n");
2129 continue; /* go and try password */
2130 } else if (pktin.type != SSH1_SMSG_SUCCESS) {
2131 bombout(
2132 ("Bizarre response to RSA authentication response"));
2133 crReturn(0);
2134 }
2135
2136 break; /* we're through! */
2137 } else {
2138 if (pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
2139 /*
2140 * Defence against traffic analysis: we send a
2141 * whole bunch of packets containing strings of
2142 * different lengths. One of these strings is the
2143 * password, in a SSH1_CMSG_AUTH_PASSWORD packet.
2144 * The others are all random data in
2145 * SSH1_MSG_IGNORE packets. This way a passive
2146 * listener can't tell which is the password, and
2147 * hence can't deduce the password length.
2148 *
2149 * Anybody with a password length greater than 16
2150 * bytes is going to have enough entropy in their
2151 * password that a listener won't find it _that_
2152 * much help to know how long it is. So what we'll
2153 * do is:
2154 *
2155 * - if password length < 16, we send 15 packets
2156 * containing string lengths 1 through 15
2157 *
2158 * - otherwise, we let N be the nearest multiple
2159 * of 8 below the password length, and send 8
2160 * packets containing string lengths N through
2161 * N+7. This won't obscure the order of
2162 * magnitude of the password length, but it will
2163 * introduce a bit of extra uncertainty.
2164 *
2165 * A few servers (the old 1.2.18 through 1.2.22)
2166 * can't deal with SSH1_MSG_IGNORE. For these
2167 * servers, we need an alternative defence. We make
2168 * use of the fact that the password is interpreted
2169 * as a C string: so we can append a NUL, then some
2170 * random data.
2171 */
2172 if (ssh_remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE) {
2173 char string[64];
2174 char *s;
2175 int len;
2176
2177 len = strlen(password);
2178 if (len < sizeof(string)) {
2179 s = string;
2180 strcpy(string, password);
2181 len++; /* cover the zero byte */
2182 while (len < sizeof(string)) {
2183 string[len++] = (char) random_byte();
2184 }
2185 } else {
2186 s = password;
2187 }
2188 send_packet(pwpkt_type, PKT_INT, len,
2189 PKT_DATA, s, len, PKT_END);
2190 } else {
2191 int bottom, top, pwlen, i;
2192 char *randomstr;
2193
2194 pwlen = strlen(password);
2195 if (pwlen < 16) {
2196 bottom = 0; /* zero length passwords are OK! :-) */
2197 top = 15;
2198 } else {
2199 bottom = pwlen & ~7;
2200 top = bottom + 7;
2201 }
2202
2203 assert(pwlen >= bottom && pwlen <= top);
2204
2205 randomstr = smalloc(top + 1);
2206
2207 for (i = bottom; i <= top; i++) {
2208 if (i == pwlen)
2209 defer_packet(pwpkt_type, PKT_STR, password,
2210 PKT_END);
2211 else {
2212 for (j = 0; j < i; j++) {
2213 do {
2214 randomstr[j] = random_byte();
2215 } while (randomstr[j] == '\0');
2216 }
2217 randomstr[i] = '\0';
2218 defer_packet(SSH1_MSG_IGNORE,
2219 PKT_STR, randomstr, PKT_END);
2220 }
2221 }
2222 ssh_pkt_defersend();
2223 }
2224 } else {
2225 send_packet(pwpkt_type, PKT_STR, password, PKT_END);
2226 }
2227 }
c5e9c988 2228 logevent("Sent password");
374330e2 2229 memset(password, 0, strlen(password));
fb09bf1c 2230 crWaitUntil(ispkt);
e5574168 2231 if (pktin.type == SSH1_SMSG_FAILURE) {
32874aea 2232 if (flags & FLAG_VERBOSE)
2233 c_write_str("Access denied\r\n");
c5e9c988 2234 logevent("Authentication refused");
e5574168 2235 } else if (pktin.type == SSH1_MSG_DISCONNECT) {
fb09bf1c 2236 logevent("Received disconnect request");
32874aea 2237 ssh_state = SSH_STATE_CLOSED;
85ee8208 2238 crReturn(1);
e5574168 2239 } else if (pktin.type != SSH1_SMSG_SUCCESS) {
8d5de777 2240 bombout(("Strange packet received, type %d", pktin.type));
32874aea 2241 crReturn(0);
374330e2 2242 }
2243 }
2244
c5e9c988 2245 logevent("Authentication successful");
2246
fb09bf1c 2247 crFinish(1);
2248}
2249
32874aea 2250void sshfwd_close(struct ssh_channel *c)
2251{
80e48603 2252 if (c && !c->closes) {
32874aea 2253 if (ssh_version == 1) {
2254 send_packet(SSH1_MSG_CHANNEL_CLOSE, PKT_INT, c->remoteid,
2255 PKT_END);
2256 } else {
2257 ssh2_pkt_init(SSH2_MSG_CHANNEL_CLOSE);
2258 ssh2_pkt_adduint32(c->remoteid);
2259 ssh2_pkt_send();
2260 }
2261 c->closes = 1;
2262 if (c->type == CHAN_X11) {
2263 c->u.x11.s = NULL;
2264 logevent("X11 connection terminated");
2265 }
2266 }
2267}
2268
2269void sshfwd_write(struct ssh_channel *c, char *buf, int len)
2270{
783415f8 2271 if (ssh_version == 1) {
32874aea 2272 send_packet(SSH1_MSG_CHANNEL_DATA,
2273 PKT_INT, c->remoteid,
2274 PKT_INT, len, PKT_DATA, buf, len, PKT_END);
783415f8 2275 } else {
32874aea 2276 ssh2_add_channel_data(c, buf, len);
2277 ssh2_try_send(c);
783415f8 2278 }
9c964e85 2279}
2280
32874aea 2281static void ssh1_protocol(unsigned char *in, int inlen, int ispkt)
2282{
fb09bf1c 2283 crBegin;
2284
2285 random_init();
2286
e5574168 2287 while (!do_ssh1_login(in, inlen, ispkt)) {
fb09bf1c 2288 crReturnV;
85ee8208 2289 }
2290 if (ssh_state == SSH_STATE_CLOSED)
32874aea 2291 crReturnV;
fb09bf1c 2292
979310f1 2293 if (cfg.agentfwd && agent_exists()) {
32874aea 2294 logevent("Requesting agent forwarding");
2295 send_packet(SSH1_CMSG_AGENT_REQUEST_FORWARDING, PKT_END);
2296 do {
2297 crReturnV;
2298 } while (!ispkt);
2299 if (pktin.type != SSH1_SMSG_SUCCESS
2300 && pktin.type != SSH1_SMSG_FAILURE) {
2301 bombout(("Protocol confusion"));
2302 crReturnV;
2303 } else if (pktin.type == SSH1_SMSG_FAILURE) {
2304 logevent("Agent forwarding refused");
2305 } else {
2306 logevent("Agent forwarding enabled");
db7d555c 2307 ssh_agentfwd_enabled = TRUE;
2308 }
dacbd0e8 2309 }
2310
9c964e85 2311 if (cfg.x11_forward) {
32874aea 2312 char proto[20], data[64];
2313 logevent("Requesting X11 forwarding");
2314 x11_invent_auth(proto, sizeof(proto), data, sizeof(data));
2315 if (ssh1_local_protoflags & SSH1_PROTOFLAG_SCREEN_NUMBER) {
2316 send_packet(SSH1_CMSG_X11_REQUEST_FORWARDING,
2317 PKT_STR, proto, PKT_STR, data,
2318 PKT_INT, 0, PKT_END);
2319 } else {
2320 send_packet(SSH1_CMSG_X11_REQUEST_FORWARDING,
2321 PKT_STR, proto, PKT_STR, data, PKT_END);
2322 }
2323 do {
2324 crReturnV;
2325 } while (!ispkt);
2326 if (pktin.type != SSH1_SMSG_SUCCESS
2327 && pktin.type != SSH1_SMSG_FAILURE) {
2328 bombout(("Protocol confusion"));
2329 crReturnV;
2330 } else if (pktin.type == SSH1_SMSG_FAILURE) {
2331 logevent("X11 forwarding refused");
2332 } else {
2333 logevent("X11 forwarding enabled");
9c964e85 2334 ssh_X11_fwd_enabled = TRUE;
2335 }
2336 }
2337
fef97f43 2338 if (!cfg.nopty) {
e5574168 2339 send_packet(SSH1_CMSG_REQUEST_PTY,
32874aea 2340 PKT_STR, cfg.termtype,
2341 PKT_INT, rows, PKT_INT, cols,
2342 PKT_INT, 0, PKT_INT, 0, PKT_CHAR, 0, PKT_END);
2343 ssh_state = SSH_STATE_INTERMED;
2344 do {
2345 crReturnV;
2346 } while (!ispkt);
2347 if (pktin.type != SSH1_SMSG_SUCCESS
2348 && pktin.type != SSH1_SMSG_FAILURE) {
2349 bombout(("Protocol confusion"));
2350 crReturnV;
2351 } else if (pktin.type == SSH1_SMSG_FAILURE) {
2352 c_write_str("Server refused to allocate pty\r\n");
2353 ssh_editing = ssh_echoing = 1;
2354 }
c5e9c988 2355 logevent("Allocated pty");
0965bee0 2356 } else {
32874aea 2357 ssh_editing = ssh_echoing = 1;
374330e2 2358 }
2359
4ba9b64b 2360 if (cfg.compression) {
32874aea 2361 send_packet(SSH1_CMSG_REQUEST_COMPRESSION, PKT_INT, 6, PKT_END);
2362 do {
2363 crReturnV;
2364 } while (!ispkt);
2365 if (pktin.type != SSH1_SMSG_SUCCESS
2366 && pktin.type != SSH1_SMSG_FAILURE) {
2367 bombout(("Protocol confusion"));
2368 crReturnV;
2369 } else if (pktin.type == SSH1_SMSG_FAILURE) {
2370 c_write_str("Server refused to compress\r\n");
2371 }
4ba9b64b 2372 logevent("Started compression");
2373 ssh1_compressing = TRUE;
2374 zlib_compress_init();
2375 zlib_decompress_init();
2376 }
2377
96621a84 2378 if (*cfg.remote_cmd_ptr)
32874aea 2379 send_packet(SSH1_CMSG_EXEC_CMD, PKT_STR, cfg.remote_cmd_ptr,
2380 PKT_END);
6abbf9e3 2381 else
32874aea 2382 send_packet(SSH1_CMSG_EXEC_SHELL, PKT_END);
c5e9c988 2383 logevent("Started session");
374330e2 2384
2385 ssh_state = SSH_STATE_SESSION;
2386 if (size_needed)
2387 ssh_size();
3687d221 2388 if (eof_needed)
32874aea 2389 ssh_special(TS_EOF);
374330e2 2390
32874aea 2391 ldisc_send(NULL, 0); /* cause ldisc to notice changes */
8ccc75b0 2392 ssh_send_ok = 1;
dacbd0e8 2393 ssh_channels = newtree234(ssh_channelcmp);
374330e2 2394 while (1) {
2395 crReturnV;
2396 if (ispkt) {
e5574168 2397 if (pktin.type == SSH1_SMSG_STDOUT_DATA ||
32874aea 2398 pktin.type == SSH1_SMSG_STDERR_DATA) {
fb09bf1c 2399 long len = GET_32BIT(pktin.body);
fe50e814 2400 from_backend(pktin.type == SSH1_SMSG_STDERR_DATA,
32874aea 2401 pktin.body + 4, len);
e5574168 2402 } else if (pktin.type == SSH1_MSG_DISCONNECT) {
32874aea 2403 ssh_state = SSH_STATE_CLOSED;
c5e9c988 2404 logevent("Received disconnect request");
32874aea 2405 crReturnV;
2406 } else if (pktin.type == SSH1_SMSG_X11_OPEN) {
2407 /* Remote side is trying to open a channel to talk to our
2408 * X-Server. Give them back a local channel number. */
2409 struct ssh_channel *c;
9c964e85 2410
2411 logevent("Received X11 connect request");
2412 /* Refuse if X11 forwarding is disabled. */
2413 if (!ssh_X11_fwd_enabled) {
2414 send_packet(SSH1_MSG_CHANNEL_OPEN_FAILURE,
32874aea 2415 PKT_INT, GET_32BIT(pktin.body), PKT_END);
9c964e85 2416 logevent("Rejected X11 connect request");
2417 } else {
9c964e85 2418 c = smalloc(sizeof(struct ssh_channel));
2419
32874aea 2420 if (x11_init(&c->u.x11.s, cfg.x11_display, c) != NULL) {
2421 logevent("opening X11 forward connection failed");
2422 sfree(c);
2423 send_packet(SSH1_MSG_CHANNEL_OPEN_FAILURE,
2424 PKT_INT, GET_32BIT(pktin.body),
2425 PKT_END);
9c964e85 2426 } else {
32874aea 2427 logevent
2428 ("opening X11 forward connection succeeded");
2429 c->remoteid = GET_32BIT(pktin.body);
2430 c->localid = alloc_channel_id();
2431 c->closes = 0;
2432 c->type = CHAN_X11; /* identify channel type */
2433 add234(ssh_channels, c);
2434 send_packet(SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
2435 PKT_INT, c->remoteid, PKT_INT,
2436 c->localid, PKT_END);
2437 logevent("Opened X11 forward channel");
9c964e85 2438 }
2439 }
32874aea 2440 } else if (pktin.type == SSH1_SMSG_AGENT_OPEN) {
2441 /* Remote side is trying to open a channel to talk to our
2442 * agent. Give them back a local channel number. */
2443 struct ssh_channel *c;
db7d555c 2444
2445 /* Refuse if agent forwarding is disabled. */
2446 if (!ssh_agentfwd_enabled) {
2447 send_packet(SSH1_MSG_CHANNEL_OPEN_FAILURE,
32874aea 2448 PKT_INT, GET_32BIT(pktin.body), PKT_END);
db7d555c 2449 } else {
dcbde236 2450 c = smalloc(sizeof(struct ssh_channel));
db7d555c 2451 c->remoteid = GET_32BIT(pktin.body);
d2371c81 2452 c->localid = alloc_channel_id();
db7d555c 2453 c->closes = 0;
32874aea 2454 c->type = CHAN_AGENT; /* identify channel type */
db7d555c 2455 c->u.a.lensofar = 0;
2456 add234(ssh_channels, c);
2457 send_packet(SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
2458 PKT_INT, c->remoteid, PKT_INT, c->localid,
2459 PKT_END);
2460 }
2461 } else if (pktin.type == SSH1_MSG_CHANNEL_CLOSE ||
2462 pktin.type == SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION) {
32874aea 2463 /* Remote side closes a channel. */
2464 unsigned i = GET_32BIT(pktin.body);
2465 struct ssh_channel *c;
2466 c = find234(ssh_channels, &i, ssh_channelfind);
2467 if (c) {
2468 int closetype;
2469 closetype =
2470 (pktin.type == SSH1_MSG_CHANNEL_CLOSE ? 1 : 2);
2471 if (!(c->closes & closetype))
2472 send_packet(pktin.type, PKT_INT, c->remoteid,
2473 PKT_END);
783415f8 2474 if ((c->closes == 0) && (c->type == CHAN_X11)) {
32874aea 2475 logevent("X11 connection closed");
9c964e85 2476 assert(c->u.x11.s != NULL);
2477 x11_close(c->u.x11.s);
2478 c->u.x11.s = NULL;
2479 }
32874aea 2480 c->closes |= closetype;
2481 if (c->closes == 3) {
2482 del234(ssh_channels, c);
2483 sfree(c);
2484 }
2485 }
2486 } else if (pktin.type == SSH1_MSG_CHANNEL_DATA) {
2487 /* Data sent down one of our channels. */
2488 int i = GET_32BIT(pktin.body);
2489 int len = GET_32BIT(pktin.body + 4);
2490 unsigned char *p = pktin.body + 8;
2491 struct ssh_channel *c;
2492 c = find234(ssh_channels, &i, ssh_channelfind);
2493 if (c) {
2494 switch (c->type) {
2495 case CHAN_X11:
9c964e85 2496 x11_send(c->u.x11.s, p, len);
2497 break;
32874aea 2498 case CHAN_AGENT:
2499 /* Data for an agent message. Buffer it. */
2500 while (len > 0) {
2501 if (c->u.a.lensofar < 4) {
2502 int l = min(4 - c->u.a.lensofar, len);
2503 memcpy(c->u.a.msglen + c->u.a.lensofar, p,
2504 l);
2505 p += l;
2506 len -= l;
2507 c->u.a.lensofar += l;
2508 }
2509 if (c->u.a.lensofar == 4) {
2510 c->u.a.totallen =
2511 4 + GET_32BIT(c->u.a.msglen);
2512 c->u.a.message = smalloc(c->u.a.totallen);
2513 memcpy(c->u.a.message, c->u.a.msglen, 4);
2514 }
2515 if (c->u.a.lensofar >= 4 && len > 0) {
2516 int l =
2517 min(c->u.a.totallen - c->u.a.lensofar,
2518 len);
2519 memcpy(c->u.a.message + c->u.a.lensofar, p,
2520 l);
2521 p += l;
2522 len -= l;
2523 c->u.a.lensofar += l;
2524 }
2525 if (c->u.a.lensofar == c->u.a.totallen) {
2526 void *reply, *sentreply;
2527 int replylen;
2528 agent_query(c->u.a.message,
2529 c->u.a.totallen, &reply,
2530 &replylen);
2531 if (reply)
2532 sentreply = reply;
2533 else {
2534 /* Fake SSH_AGENT_FAILURE. */
2535 sentreply = "\0\0\0\1\5";
2536 replylen = 5;
2537 }
2538 send_packet(SSH1_MSG_CHANNEL_DATA,
2539 PKT_INT, c->remoteid,
2540 PKT_INT, replylen,
2541 PKT_DATA, sentreply, replylen,
2542 PKT_END);
2543 if (reply)
2544 sfree(reply);
2545 sfree(c->u.a.message);
2546 c->u.a.lensofar = 0;
2547 }
2548 }
2549 break;
2550 }
2551 }
e5574168 2552 } else if (pktin.type == SSH1_SMSG_SUCCESS) {
972a41c8 2553 /* may be from EXEC_SHELL on some servers */
e5574168 2554 } else if (pktin.type == SSH1_SMSG_FAILURE) {
972a41c8 2555 /* may be from EXEC_SHELL on some servers
374330e2 2556 * if no pty is available or in other odd cases. Ignore */
e5574168 2557 } else if (pktin.type == SSH1_SMSG_EXIT_STATUS) {
2558 send_packet(SSH1_CMSG_EXIT_CONFIRMATION, PKT_END);
374330e2 2559 } else {
8d5de777 2560 bombout(("Strange packet received: type %d", pktin.type));
32874aea 2561 crReturnV;
374330e2 2562 }
2563 } else {
8df7a775 2564 while (inlen > 0) {
2565 int len = min(inlen, 512);
2566 send_packet(SSH1_CMSG_STDIN_DATA,
2567 PKT_INT, len, PKT_DATA, in, len, PKT_END);
2568 in += len;
2569 inlen -= len;
2570 }
374330e2 2571 }
2572 }
2573
2574 crFinishV;
2575}
2576
2577/*
e5574168 2578 * Utility routine for decoding comma-separated strings in KEXINIT.
2579 */
32874aea 2580static int in_commasep_string(char *needle, char *haystack, int haylen)
2581{
e5574168 2582 int needlen = strlen(needle);
2583 while (1) {
32874aea 2584 /*
2585 * Is it at the start of the string?
2586 */
2587 if (haylen >= needlen && /* haystack is long enough */
2588 !memcmp(needle, haystack, needlen) && /* initial match */
2589 (haylen == needlen || haystack[needlen] == ',')
2590 /* either , or EOS follows */
2591 )
2592 return 1;
2593 /*
2594 * If not, search for the next comma and resume after that.
2595 * If no comma found, terminate.
2596 */
2597 while (haylen > 0 && *haystack != ',')
2598 haylen--, haystack++;
2599 if (haylen == 0)
2600 return 0;
2601 haylen--, haystack++; /* skip over comma itself */
e5574168 2602 }
2603}
2604
2605/*
d39f364a 2606 * SSH2 key creation method.
2607 */
32874aea 2608static void ssh2_mkkey(Bignum K, char *H, char *sessid, char chr,
2609 char *keyspace)
2610{
d39f364a 2611 SHA_State s;
2612 /* First 20 bytes. */
2613 SHA_Init(&s);
2614 sha_mpint(&s, K);
2615 SHA_Bytes(&s, H, 20);
2616 SHA_Bytes(&s, &chr, 1);
5e0d7cb8 2617 SHA_Bytes(&s, sessid, 20);
d39f364a 2618 SHA_Final(&s, keyspace);
2619 /* Next 20 bytes. */
2620 SHA_Init(&s);
2621 sha_mpint(&s, K);
2622 SHA_Bytes(&s, H, 20);
2623 SHA_Bytes(&s, keyspace, 20);
32874aea 2624 SHA_Final(&s, keyspace + 20);
d39f364a 2625}
2626
2627/*
7cca0d81 2628 * Handle the SSH2 transport layer.
e5574168 2629 */
7cca0d81 2630static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt)
e5574168 2631{
7bd5a860 2632 static int i, j, len, nbits, pbits;
e5574168 2633 static char *str;
a92dd380 2634 static Bignum p, g, e, f, K;
2635 static int kex_init_value, kex_reply_value;
7591b9ff 2636 static const struct ssh_mac **maclist;
8b2715b2 2637 static int nmacs;
0a3f1d48 2638 static const struct ssh2_cipher *cscipher_tobe = NULL;
2639 static const struct ssh2_cipher *sccipher_tobe = NULL;
57476f6b 2640 static const struct ssh_mac *csmac_tobe = NULL;
2641 static const struct ssh_mac *scmac_tobe = NULL;
2642 static const struct ssh_compress *cscomp_tobe = NULL;
2643 static const struct ssh_compress *sccomp_tobe = NULL;
d5859615 2644 static char *hostkeydata, *sigdata, *keystr, *fingerprint;
e5574168 2645 static int hostkeylen, siglen;
e055a386 2646 static void *hkey; /* actual host key */
e5574168 2647 static unsigned char exchange_hash[20];
d39f364a 2648 static unsigned char keyspace[40];
0a3f1d48 2649 static const struct ssh2_ciphers *preferred_cipher;
4ba9b64b 2650 static const struct ssh_compress *preferred_comp;
0db56f73 2651 static int first_kex;
e5574168 2652
2653 crBegin;
7cca0d81 2654 random_init();
0db56f73 2655 first_kex = 1;
e5574168 2656
5e8358ad 2657 /*
4ba9b64b 2658 * Set up the preferred cipher and compression.
5e8358ad 2659 */
2660 if (cfg.cipher == CIPHER_BLOWFISH) {
32874aea 2661 preferred_cipher = &ssh2_blowfish;
5e8358ad 2662 } else if (cfg.cipher == CIPHER_DES) {
32874aea 2663 logevent("Single DES not supported in SSH2; using 3DES");
2664 preferred_cipher = &ssh2_3des;
5e8358ad 2665 } else if (cfg.cipher == CIPHER_3DES) {
32874aea 2666 preferred_cipher = &ssh2_3des;
0a3f1d48 2667 } else if (cfg.cipher == CIPHER_AES) {
32874aea 2668 preferred_cipher = &ssh2_aes;
5e8358ad 2669 } else {
32874aea 2670 /* Shouldn't happen, but we do want to initialise to _something_. */
2671 preferred_cipher = &ssh2_3des;
5e8358ad 2672 }
4ba9b64b 2673 if (cfg.compression)
2674 preferred_comp = &ssh_zlib;
2675 else
2676 preferred_comp = &ssh_comp_none;
5e8358ad 2677
7591b9ff 2678 /*
2679 * Be prepared to work around the buggy MAC problem.
2680 */
7d503c31 2681 if (cfg.buggymac || (ssh_remote_bugs & BUG_SSH2_HMAC))
32874aea 2682 maclist = buggymacs, nmacs = lenof(buggymacs);
7591b9ff 2683 else
32874aea 2684 maclist = macs, nmacs = lenof(macs);
7591b9ff 2685
32874aea 2686 begin_key_exchange:
e5574168 2687 /*
2688 * Construct and send our key exchange packet.
2689 */
2690 ssh2_pkt_init(SSH2_MSG_KEXINIT);
2691 for (i = 0; i < 16; i++)
32874aea 2692 ssh2_pkt_addbyte((unsigned char) random_byte());
e5574168 2693 /* List key exchange algorithms. */
2694 ssh2_pkt_addstring_start();
2695 for (i = 0; i < lenof(kex_algs); i++) {
32874aea 2696 ssh2_pkt_addstring_str(kex_algs[i]->name);
2697 if (i < lenof(kex_algs) - 1)
2698 ssh2_pkt_addstring_str(",");
e5574168 2699 }
2700 /* List server host key algorithms. */
2701 ssh2_pkt_addstring_start();
2702 for (i = 0; i < lenof(hostkey_algs); i++) {
32874aea 2703 ssh2_pkt_addstring_str(hostkey_algs[i]->name);
2704 if (i < lenof(hostkey_algs) - 1)
2705 ssh2_pkt_addstring_str(",");
e5574168 2706 }
2707 /* List client->server encryption algorithms. */
2708 ssh2_pkt_addstring_start();
32874aea 2709 for (i = 0; i < lenof(ciphers) + 1; i++) {
2710 const struct ssh2_ciphers *c =
2711 i == 0 ? preferred_cipher : ciphers[i - 1];
2712 for (j = 0; j < c->nciphers; j++) {
2713 ssh2_pkt_addstring_str(c->list[j]->name);
2714 if (i < lenof(ciphers) || j < c->nciphers - 1)
2715 ssh2_pkt_addstring_str(",");
2716 }
e5574168 2717 }
2718 /* List server->client encryption algorithms. */
2719 ssh2_pkt_addstring_start();
32874aea 2720 for (i = 0; i < lenof(ciphers) + 1; i++) {
2721 const struct ssh2_ciphers *c =
2722 i == 0 ? preferred_cipher : ciphers[i - 1];
2723 for (j = 0; j < c->nciphers; j++) {
2724 ssh2_pkt_addstring_str(c->list[j]->name);
2725 if (i < lenof(ciphers) || j < c->nciphers - 1)
2726 ssh2_pkt_addstring_str(",");
2727 }
e5574168 2728 }
2729 /* List client->server MAC algorithms. */
2730 ssh2_pkt_addstring_start();
8b2715b2 2731 for (i = 0; i < nmacs; i++) {
32874aea 2732 ssh2_pkt_addstring_str(maclist[i]->name);
2733 if (i < nmacs - 1)
2734 ssh2_pkt_addstring_str(",");
e5574168 2735 }
2736 /* List server->client MAC algorithms. */
2737 ssh2_pkt_addstring_start();
8b2715b2 2738 for (i = 0; i < nmacs; i++) {
32874aea 2739 ssh2_pkt_addstring_str(maclist[i]->name);
2740 if (i < nmacs - 1)
2741 ssh2_pkt_addstring_str(",");
e5574168 2742 }
2743 /* List client->server compression algorithms. */
2744 ssh2_pkt_addstring_start();
32874aea 2745 for (i = 0; i < lenof(compressions) + 1; i++) {
2746 const struct ssh_compress *c =
2747 i == 0 ? preferred_comp : compressions[i - 1];
2748 ssh2_pkt_addstring_str(c->name);
2749 if (i < lenof(compressions))
2750 ssh2_pkt_addstring_str(",");
e5574168 2751 }
2752 /* List server->client compression algorithms. */
2753 ssh2_pkt_addstring_start();
32874aea 2754 for (i = 0; i < lenof(compressions) + 1; i++) {
2755 const struct ssh_compress *c =
2756 i == 0 ? preferred_comp : compressions[i - 1];
2757 ssh2_pkt_addstring_str(c->name);
2758 if (i < lenof(compressions))
2759 ssh2_pkt_addstring_str(",");
e5574168 2760 }
2761 /* List client->server languages. Empty list. */
2762 ssh2_pkt_addstring_start();
2763 /* List server->client languages. Empty list. */
2764 ssh2_pkt_addstring_start();
2765 /* First KEX packet does _not_ follow, because we're not that brave. */
2766 ssh2_pkt_addbool(FALSE);
2767 /* Reserved. */
2768 ssh2_pkt_adduint32(0);
0db56f73 2769
2770 exhash = exhashbase;
32874aea 2771 sha_string(&exhash, pktout.data + 5, pktout.length - 5);
0db56f73 2772
e5574168 2773 ssh2_pkt_send();
2774
32874aea 2775 if (!ispkt)
2776 crWaitUntil(ispkt);
2777 sha_string(&exhash, pktin.data + 5, pktin.length - 5);
e5574168 2778
2779 /*
2780 * Now examine the other side's KEXINIT to see what we're up
2781 * to.
2782 */
7cca0d81 2783 if (pktin.type != SSH2_MSG_KEXINIT) {
32874aea 2784 bombout(("expected key exchange packet from server"));
2785 crReturn(0);
7cca0d81 2786 }
32874aea 2787 kex = NULL;
2788 hostkey = NULL;
2789 cscipher_tobe = NULL;
2790 sccipher_tobe = NULL;
2791 csmac_tobe = NULL;
2792 scmac_tobe = NULL;
2793 cscomp_tobe = NULL;
2794 sccomp_tobe = NULL;
2795 pktin.savedpos += 16; /* skip garbage cookie */
e5574168 2796 ssh2_pkt_getstring(&str, &len); /* key exchange algorithms */
2797 for (i = 0; i < lenof(kex_algs); i++) {
32874aea 2798 if (in_commasep_string(kex_algs[i]->name, str, len)) {
2799 kex = kex_algs[i];
2800 break;
2801 }
e5574168 2802 }
2803 ssh2_pkt_getstring(&str, &len); /* host key algorithms */
2804 for (i = 0; i < lenof(hostkey_algs); i++) {
32874aea 2805 if (in_commasep_string(hostkey_algs[i]->name, str, len)) {
2806 hostkey = hostkey_algs[i];
2807 break;
2808 }
e5574168 2809 }
2810 ssh2_pkt_getstring(&str, &len); /* client->server cipher */
32874aea 2811 for (i = 0; i < lenof(ciphers) + 1; i++) {
2812 const struct ssh2_ciphers *c =
2813 i == 0 ? preferred_cipher : ciphers[i - 1];
2814 for (j = 0; j < c->nciphers; j++) {
2815 if (in_commasep_string(c->list[j]->name, str, len)) {
2816 cscipher_tobe = c->list[j];
2817 break;
2818 }
2819 }
2820 if (cscipher_tobe)
2821 break;
e5574168 2822 }
2823 ssh2_pkt_getstring(&str, &len); /* server->client cipher */
32874aea 2824 for (i = 0; i < lenof(ciphers) + 1; i++) {
2825 const struct ssh2_ciphers *c =
2826 i == 0 ? preferred_cipher : ciphers[i - 1];
2827 for (j = 0; j < c->nciphers; j++) {
2828 if (in_commasep_string(c->list[j]->name, str, len)) {
2829 sccipher_tobe = c->list[j];
2830 break;
2831 }
2832 }
2833 if (sccipher_tobe)
2834 break;
e5574168 2835 }
2836 ssh2_pkt_getstring(&str, &len); /* client->server mac */
8b2715b2 2837 for (i = 0; i < nmacs; i++) {
32874aea 2838 if (in_commasep_string(maclist[i]->name, str, len)) {
2839 csmac_tobe = maclist[i];
2840 break;
2841 }
e5574168 2842 }
2843 ssh2_pkt_getstring(&str, &len); /* server->client mac */
8b2715b2 2844 for (i = 0; i < nmacs; i++) {
32874aea 2845 if (in_commasep_string(maclist[i]->name, str, len)) {
2846 scmac_tobe = maclist[i];
2847 break;
2848 }
e5574168 2849 }
2850 ssh2_pkt_getstring(&str, &len); /* client->server compression */
32874aea 2851 for (i = 0; i < lenof(compressions) + 1; i++) {
2852 const struct ssh_compress *c =
2853 i == 0 ? preferred_comp : compressions[i - 1];
2854 if (in_commasep_string(c->name, str, len)) {
2855 cscomp_tobe = c;
2856 break;
2857 }
e5574168 2858 }
2859 ssh2_pkt_getstring(&str, &len); /* server->client compression */
32874aea 2860 for (i = 0; i < lenof(compressions) + 1; i++) {
2861 const struct ssh_compress *c =
2862 i == 0 ? preferred_comp : compressions[i - 1];
2863 if (in_commasep_string(c->name, str, len)) {
2864 sccomp_tobe = c;
2865 break;
2866 }
e5574168 2867 }
e5574168 2868
2869 /*
7bd5a860 2870 * Work out the number of bits of key we will need from the key
2871 * exchange. We start with the maximum key length of either
2872 * cipher...
2873 */
2874 {
32874aea 2875 int csbits, scbits;
7bd5a860 2876
2877 csbits = cscipher_tobe->keylen;
2878 scbits = sccipher_tobe->keylen;
2879 nbits = (csbits > scbits ? csbits : scbits);
2880 }
2881 /* The keys only have 160-bit entropy, since they're based on
2882 * a SHA-1 hash. So cap the key size at 160 bits. */
32874aea 2883 if (nbits > 160)
2884 nbits = 160;
7bd5a860 2885
2886 /*
a92dd380 2887 * If we're doing Diffie-Hellman group exchange, start by
2888 * requesting a group.
e5574168 2889 */
a92dd380 2890 if (kex == &ssh_diffiehellman_gex) {
32874aea 2891 logevent("Doing Diffie-Hellman group exchange");
2892 /*
2893 * Work out how big a DH group we will need to allow that
2894 * much data.
7bd5a860 2895 */
32874aea 2896 pbits = 512 << ((nbits - 1) / 64);
2897 ssh2_pkt_init(SSH2_MSG_KEX_DH_GEX_REQUEST);
2898 ssh2_pkt_adduint32(pbits);
2899 ssh2_pkt_send();
2900
2901 crWaitUntil(ispkt);
2902 if (pktin.type != SSH2_MSG_KEX_DH_GEX_GROUP) {
2903 bombout(("expected key exchange group packet from server"));
2904 crReturn(0);
2905 }
2906 p = ssh2_pkt_getmp();
2907 g = ssh2_pkt_getmp();
2908 dh_setup_group(p, g);
2909 kex_init_value = SSH2_MSG_KEX_DH_GEX_INIT;
2910 kex_reply_value = SSH2_MSG_KEX_DH_GEX_REPLY;
a92dd380 2911 } else {
32874aea 2912 dh_setup_group1();
2913 kex_init_value = SSH2_MSG_KEXDH_INIT;
2914 kex_reply_value = SSH2_MSG_KEXDH_REPLY;
8d5de777 2915 }
e5574168 2916
a92dd380 2917 logevent("Doing Diffie-Hellman key exchange");
e5574168 2918 /*
a92dd380 2919 * Now generate and send e for Diffie-Hellman.
e5574168 2920 */
32874aea 2921 e = dh_create_e(nbits * 2);
a92dd380 2922 ssh2_pkt_init(kex_init_value);
e5574168 2923 ssh2_pkt_addmp(e);
2924 ssh2_pkt_send();
2925
2926 crWaitUntil(ispkt);
a92dd380 2927 if (pktin.type != kex_reply_value) {
32874aea 2928 bombout(("expected key exchange reply packet from server"));
2929 crReturn(0);
7cca0d81 2930 }
e5574168 2931 ssh2_pkt_getstring(&hostkeydata, &hostkeylen);
2932 f = ssh2_pkt_getmp();
e5574168 2933 ssh2_pkt_getstring(&sigdata, &siglen);
2934
2935 K = dh_find_K(f);
e5574168 2936
2937 sha_string(&exhash, hostkeydata, hostkeylen);
a92dd380 2938 if (kex == &ssh_diffiehellman_gex) {
32874aea 2939 sha_uint32(&exhash, pbits);
2940 sha_mpint(&exhash, p);
2941 sha_mpint(&exhash, g);
a92dd380 2942 }
e5574168 2943 sha_mpint(&exhash, e);
2944 sha_mpint(&exhash, f);
2945 sha_mpint(&exhash, K);
2946 SHA_Final(&exhash, exchange_hash);
2947
3709bfe9 2948 dh_cleanup();
2949
7cca0d81 2950#if 0
765c4200 2951 debug(("Exchange hash is:\n"));
2952 dmemdump(exchange_hash, 20);
7cca0d81 2953#endif
2954
e055a386 2955 hkey = hostkey->newkey(hostkeydata, hostkeylen);
2956 if (!hostkey->verifysig(hkey, sigdata, siglen, exchange_hash, 20)) {
32874aea 2957 bombout(("Server failed host key check"));
2958 crReturn(0);
8d5de777 2959 }
e5574168 2960
2961 /*
7cca0d81 2962 * Expect SSH2_MSG_NEWKEYS from server.
d39f364a 2963 */
7cca0d81 2964 crWaitUntil(ispkt);
8d5de777 2965 if (pktin.type != SSH2_MSG_NEWKEYS) {
32874aea 2966 bombout(("expected new-keys packet from server"));
2967 crReturn(0);
8d5de777 2968 }
d39f364a 2969
2970 /*
7cca0d81 2971 * Authenticate remote host: verify host key. (We've already
2972 * checked the signature of the exchange hash.)
e5574168 2973 */
e055a386 2974 keystr = hostkey->fmtkey(hkey);
2975 fingerprint = hostkey->fingerprint(hkey);
d4857987 2976 verify_ssh_host_key(savedhost, savedport, hostkey->keytype,
32874aea 2977 keystr, fingerprint);
2978 if (first_kex) { /* don't bother logging this in rekeys */
5e0d7cb8 2979 logevent("Host key fingerprint is:");
2980 logevent(fingerprint);
2981 }
dcbde236 2982 sfree(fingerprint);
2983 sfree(keystr);
e055a386 2984 hostkey->freekey(hkey);
d39f364a 2985
2986 /*
7cca0d81 2987 * Send SSH2_MSG_NEWKEYS.
d39f364a 2988 */
2989 ssh2_pkt_init(SSH2_MSG_NEWKEYS);
2990 ssh2_pkt_send();
d39f364a 2991
2992 /*
2993 * Create and initialise session keys.
2994 */
2995 cscipher = cscipher_tobe;
2996 sccipher = sccipher_tobe;
2997 csmac = csmac_tobe;
2998 scmac = scmac_tobe;
2999 cscomp = cscomp_tobe;
3000 sccomp = sccomp_tobe;
4ba9b64b 3001 cscomp->compress_init();
3002 sccomp->decompress_init();
d39f364a 3003 /*
5e0d7cb8 3004 * Set IVs after keys. Here we use the exchange hash from the
3005 * _first_ key exchange.
d39f364a 3006 */
5e0d7cb8 3007 if (first_kex)
65a22376 3008 memcpy(ssh2_session_id, exchange_hash, sizeof(exchange_hash));
3009 ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'C', keyspace);
5e0d7cb8 3010 cscipher->setcskey(keyspace);
65a22376 3011 ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'D', keyspace);
5e0d7cb8 3012 sccipher->setsckey(keyspace);
65a22376 3013 ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'A', keyspace);
5e0d7cb8 3014 cscipher->setcsiv(keyspace);
65a22376 3015 ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'B', keyspace);
5e0d7cb8 3016 sccipher->setsciv(keyspace);
65a22376 3017 ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'E', keyspace);
5e0d7cb8 3018 csmac->setcskey(keyspace);
65a22376 3019 ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'F', keyspace);
5e0d7cb8 3020 scmac->setsckey(keyspace);
d39f364a 3021
033b4cef 3022 /*
0db56f73 3023 * If this is the first key exchange phase, we must pass the
3024 * SSH2_MSG_NEWKEYS packet to the next layer, not because it
3025 * wants to see it but because it will need time to initialise
3026 * itself before it sees an actual packet. In subsequent key
3027 * exchange phases, we don't pass SSH2_MSG_NEWKEYS on, because
3028 * it would only confuse the layer above.
3029 */
3030 if (!first_kex) {
32874aea 3031 crReturn(0);
0db56f73 3032 }
3033 first_kex = 0;
3034
3035 /*
7cca0d81 3036 * Now we're encrypting. Begin returning 1 to the protocol main
3037 * function so that other things can run on top of the
3038 * transport. If we ever see a KEXINIT, we must go back to the
3039 * start.
033b4cef 3040 */
e96adf72 3041 while (!(ispkt && pktin.type == SSH2_MSG_KEXINIT)) {
32874aea 3042 crReturn(1);
e96adf72 3043 }
5e0d7cb8 3044 logevent("Server initiated key re-exchange");
7cca0d81 3045 goto begin_key_exchange;
e5574168 3046
3047 crFinish(1);
3048}
3049
7cca0d81 3050/*
783415f8 3051 * Add data to an SSH2 channel output buffer.
3052 */
32874aea 3053static void ssh2_add_channel_data(struct ssh_channel *c, char *buf,
3054 int len)
3055{
3056 if (c->v2.outbufsize < c->v2.outbuflen + len) {
3057 c->v2.outbufsize = c->v2.outbuflen + len + 1024;
3058 c->v2.outbuffer = srealloc(c->v2.outbuffer, c->v2.outbufsize);
3059 }
3060 memcpy(c->v2.outbuffer + c->v2.outbuflen, buf, len);
783415f8 3061 c->v2.outbuflen += len;
3062}
3063
3064/*
3065 * Attempt to send data on an SSH2 channel.
3066 */
32874aea 3067static void ssh2_try_send(struct ssh_channel *c)
3068{
3069 while (c->v2.remwindow > 0 && c->v2.outbuflen > 0) {
3070 unsigned len = c->v2.remwindow;
3071 if (len > c->v2.outbuflen)
3072 len = c->v2.outbuflen;
3073 if (len > c->v2.remmaxpkt)
3074 len = c->v2.remmaxpkt;
3075 ssh2_pkt_init(SSH2_MSG_CHANNEL_DATA);
3076 ssh2_pkt_adduint32(c->remoteid);
3077 ssh2_pkt_addstring_start();
3078 ssh2_pkt_addstring_data(c->v2.outbuffer, len);
3079 ssh2_pkt_send();
3080 c->v2.outbuflen -= len;
3081 memmove(c->v2.outbuffer, c->v2.outbuffer + len, c->v2.outbuflen);
3082 c->v2.remwindow -= len;
783415f8 3083 }
3084}
3085
3086/*
7cca0d81 3087 * Handle the SSH2 userauth and connection layers.
3088 */
3089static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt)
3090{
65a22376 3091 static enum {
32874aea 3092 AUTH_INVALID, AUTH_PUBLICKEY_AGENT, AUTH_PUBLICKEY_FILE,
3093 AUTH_PASSWORD
65a22376 3094 } method;
1408a877 3095 static enum {
32874aea 3096 AUTH_TYPE_NONE,
3097 AUTH_TYPE_PUBLICKEY,
3098 AUTH_TYPE_PUBLICKEY_OFFER_LOUD,
3099 AUTH_TYPE_PUBLICKEY_OFFER_QUIET,
3100 AUTH_TYPE_PASSWORD
1408a877 3101 } type;
1983e559 3102 static int gotit, need_pw, can_pubkey, can_passwd;
3103 static int tried_pubkey_config, tried_agent;
1408a877 3104 static int we_are_in;
65a22376 3105 static char username[100];
3106 static char pwprompt[200];
3107 static char password[100];
7cca0d81 3108
e5574168 3109 crBegin;
3110
7cca0d81 3111 /*
3112 * Request userauth protocol, and await a response to it.
3113 */
3114 ssh2_pkt_init(SSH2_MSG_SERVICE_REQUEST);
3115 ssh2_pkt_addstring("ssh-userauth");
3116 ssh2_pkt_send();
3117 crWaitUntilV(ispkt);
8d5de777 3118 if (pktin.type != SSH2_MSG_SERVICE_ACCEPT) {
32874aea 3119 bombout(("Server refused user authentication protocol"));
3120 crReturnV;
8d5de777 3121 }
7cca0d81 3122
3123 /*
1408a877 3124 * We repeat this whole loop, including the username prompt,
3125 * until we manage a successful authentication. If the user
3126 * types the wrong _password_, they are sent back to the
3127 * beginning to try another username. (If they specify a
3128 * username in the config, they are never asked, even if they
3129 * do give a wrong password.)
3130 *
3131 * I think this best serves the needs of
3132 *
3133 * - the people who have no configuration, no keys, and just
3134 * want to try repeated (username,password) pairs until they
3135 * type both correctly
3136 *
3137 * - people who have keys and configuration but occasionally
3138 * need to fall back to passwords
3139 *
3140 * - people with a key held in Pageant, who might not have
3141 * logged in to a particular machine before; so they want to
3142 * type a username, and then _either_ their key will be
3143 * accepted, _or_ they will type a password. If they mistype
3144 * the username they will want to be able to get back and
3145 * retype it!
7cca0d81 3146 */
1408a877 3147 do {
3148 static int pos;
7cca0d81 3149 static char c;
e5574168 3150
1408a877 3151 /*
3152 * Get a username.
3153 */
3154 pos = 0;
67779be7 3155 if ((flags & FLAG_INTERACTIVE) && !*cfg.username) {
32874aea 3156 if (ssh_get_line) {
3157 if (!ssh_get_line("login as: ",
3158 username, sizeof(username), FALSE)) {
3159 /*
3160 * get_line failed to get a username.
3161 * Terminate.
3162 */
3163 logevent("No username provided. Abandoning session.");
3164 ssh_state = SSH_STATE_CLOSED;
3165 crReturnV;
3166 }
3167 } else {
3168 c_write_str("login as: ");
3169 ssh_send_ok = 1;
3170 while (pos >= 0) {
3171 crWaitUntilV(!ispkt);
3172 while (inlen--)
3173 switch (c = *in++) {
3174 case 10:
3175 case 13:
3176 username[pos] = 0;
3177 pos = -1;
3178 break;
3179 case 8:
3180 case 127:
3181 if (pos > 0) {
3182 c_write_str("\b \b");
3183 pos--;
3184 }
3185 break;
3186 case 21:
3187 case 27:
3188 while (pos > 0) {
3189 c_write_str("\b \b");
3190 pos--;
3191 }
3192 break;
3193 case 3:
3194 case 4:
3195 random_save_seed();
3196 exit(0);
3197 break;
3198 default:
3199 if (((c >= ' ' && c <= '~') ||
51b2fb65 3200 ((unsigned char) c >= 160))
3201 && pos < sizeof(username)-1) {
32874aea 3202 username[pos++] = c;
3203 c_write(&c, 1);
3204 }
3205 break;
3206 }
3207 }
3208 }
1408a877 3209 c_write_str("\r\n");
7cca0d81 3210 username[strcspn(username, "\n\r")] = '\0';
3211 } else {
3212 char stuff[200];
3213 strncpy(username, cfg.username, 99);
3214 username[99] = '\0';
65a22376 3215 if ((flags & FLAG_VERBOSE) || (flags & FLAG_INTERACTIVE)) {
7cca0d81 3216 sprintf(stuff, "Using username \"%s\".\r\n", username);
1408a877 3217 c_write_str(stuff);
7cca0d81 3218 }
3219 }
3220
65a22376 3221 /*
1408a877 3222 * Send an authentication request using method "none": (a)
3223 * just in case it succeeds, and (b) so that we know what
3224 * authentication methods we can usefully try next.
65a22376 3225 */
1408a877 3226 ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
3227 ssh2_pkt_addstring(username);
32874aea 3228 ssh2_pkt_addstring("ssh-connection"); /* service requested */
1408a877 3229 ssh2_pkt_addstring("none"); /* method */
3230 ssh2_pkt_send();
3231 type = AUTH_TYPE_NONE;
3232 gotit = FALSE;
3233 we_are_in = FALSE;
7cca0d81 3234
1408a877 3235 tried_pubkey_config = FALSE;
1983e559 3236 tried_agent = FALSE;
65a22376 3237
1408a877 3238 while (1) {
3239 /*
3240 * Wait for the result of the last authentication request.
3241 */
3242 if (!gotit)
3243 crWaitUntilV(ispkt);
3244 while (pktin.type == SSH2_MSG_USERAUTH_BANNER) {
32874aea 3245 char *banner;
3246 int size;
3247 /*
3248 * Don't show the banner if we're operating in
3249 * non-verbose non-interactive mode. (It's probably
3250 * a script, which means nobody will read the
3251 * banner _anyway_, and moreover the printing of
3252 * the banner will screw up processing on the
3253 * output of (say) plink.)
3254 */
3255 if (flags & (FLAG_VERBOSE | FLAG_INTERACTIVE)) {
3256 ssh2_pkt_getstring(&banner, &size);
3257 if (banner)
3258 c_write_untrusted(banner, size);
3259 }
1408a877 3260 crWaitUntilV(ispkt);
3261 }
3262 if (pktin.type == SSH2_MSG_USERAUTH_SUCCESS) {
3263 logevent("Access granted");
3264 we_are_in = TRUE;
3265 break;
3266 }
65a22376 3267
1408a877 3268 if (pktin.type != SSH2_MSG_USERAUTH_FAILURE) {
32874aea 3269 bombout(
3270 ("Strange packet received during authentication: type %d",
1408a877 3271 pktin.type));
38c4a8da 3272 crReturnV;
65a22376 3273 }
3274
1408a877 3275 gotit = FALSE;
65a22376 3276
1408a877 3277 /*
3278 * OK, we're now sitting on a USERAUTH_FAILURE message, so
3279 * we can look at the string in it and know what we can
3280 * helpfully try next.
3281 */
3282 {
3283 char *methods;
3284 int methlen;
3285 ssh2_pkt_getstring(&methods, &methlen);
3286 if (!ssh2_pkt_getbool()) {
3287 /*
3288 * We have received an unequivocal Access
3289 * Denied. This can translate to a variety of
3290 * messages:
3291 *
3292 * - if we'd just tried "none" authentication,
3293 * it's not worth printing anything at all
3294 *
3295 * - if we'd just tried a public key _offer_,
3296 * the message should be "Server refused our
3297 * key" (or no message at all if the key
3298 * came from Pageant)
3299 *
3300 * - if we'd just tried anything else, the
3301 * message really should be "Access denied".
3302 *
3303 * Additionally, if we'd just tried password
3304 * authentication, we should break out of this
3305 * whole loop so as to go back to the username
3306 * prompt.
3307 */
3308 if (type == AUTH_TYPE_NONE) {
3309 /* do nothing */
3310 } else if (type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD ||
3311 type == AUTH_TYPE_PUBLICKEY_OFFER_QUIET) {
3312 if (type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD)
3313 c_write_str("Server refused our key\r\n");
3314 logevent("Server refused public key");
3315 } else {
3316 c_write_str("Access denied\r\n");
3317 logevent("Access denied");
3318 if (type == AUTH_TYPE_PASSWORD) {
3319 we_are_in = FALSE;
3320 break;
3321 }
3322 }
3323 } else {
3324 c_write_str("Further authentication required\r\n");
3325 logevent("Further authentication required");
3326 }
65a22376 3327
32874aea 3328 can_pubkey =
3329 in_commasep_string("publickey", methods, methlen);
3330 can_passwd =
3331 in_commasep_string("password", methods, methlen);
1408a877 3332 }
65a22376 3333
1408a877 3334 method = 0;
65a22376 3335
78afa559 3336 if (!method && can_pubkey && agent_exists() && !tried_agent) {
1983e559 3337 /*
3338 * Attempt public-key authentication using Pageant.
3339 */
3340 static unsigned char request[5], *response, *p;
3341 static int responselen;
3342 static int i, nkeys;
3343 static int authed = FALSE;
3344 void *r;
3345
3346 tried_agent = TRUE;
3347
3348 logevent("Pageant is running. Requesting keys.");
3349
3350 /* Request the keys held by the agent. */
3351 PUT_32BIT(request, 1);
3352 request[4] = SSH2_AGENTC_REQUEST_IDENTITIES;
3353 agent_query(request, 5, &r, &responselen);
32874aea 3354 response = (unsigned char *) r;
95797139 3355 if (response && responselen >= 5 &&
32874aea 3356 response[4] == SSH2_AGENT_IDENTITIES_ANSWER) {
1983e559 3357 p = response + 5;
32874aea 3358 nkeys = GET_32BIT(p);
3359 p += 4;
3360 {
3361 char buf[64];
3362 sprintf(buf, "Pageant has %d SSH2 keys", nkeys);
3363 logevent(buf);
3364 }
1983e559 3365 for (i = 0; i < nkeys; i++) {
3366 static char *pkblob, *alg, *commentp;
3367 static int pklen, alglen, commentlen;
3368 static int siglen, retlen, len;
3369 static char *q, *agentreq, *ret;
2d466ffd 3370 void *vret;
1983e559 3371
32874aea 3372 {
3373 char buf[64];
3374 sprintf(buf, "Trying Pageant key #%d", i);
3375 logevent(buf);
3376 }
3377 pklen = GET_32BIT(p);
3378 p += 4;
3379 pkblob = p;
3380 p += pklen;
1983e559 3381 alglen = GET_32BIT(pkblob);
3382 alg = pkblob + 4;
32874aea 3383 commentlen = GET_32BIT(p);
3384 p += 4;
3385 commentp = p;
3386 p += commentlen;
1983e559 3387 ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
3388 ssh2_pkt_addstring(username);
32874aea 3389 ssh2_pkt_addstring("ssh-connection"); /* service requested */
3390 ssh2_pkt_addstring("publickey"); /* method */
3391 ssh2_pkt_addbool(FALSE); /* no signature included */
1983e559 3392 ssh2_pkt_addstring_start();
3393 ssh2_pkt_addstring_data(alg, alglen);
3394 ssh2_pkt_addstring_start();
3395 ssh2_pkt_addstring_data(pkblob, pklen);
3396 ssh2_pkt_send();
3397
3398 crWaitUntilV(ispkt);
3399 if (pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
3400 logevent("Key refused");
3401 continue;
3402 }
3403
32874aea 3404 if (flags & FLAG_VERBOSE) {
3405 c_write_str
3406 ("Authenticating with public key \"");
3407 c_write(commentp, commentlen);
3408 c_write_str("\" from agent\r\n");
3409 }
1983e559 3410
3411 /*
3412 * Server is willing to accept the key.
3413 * Construct a SIGN_REQUEST.
3414 */
3415 ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
3416 ssh2_pkt_addstring(username);
32874aea 3417 ssh2_pkt_addstring("ssh-connection"); /* service requested */
3418 ssh2_pkt_addstring("publickey"); /* method */
1983e559 3419 ssh2_pkt_addbool(TRUE);
3420 ssh2_pkt_addstring_start();
3421 ssh2_pkt_addstring_data(alg, alglen);
3422 ssh2_pkt_addstring_start();
3423 ssh2_pkt_addstring_data(pkblob, pklen);
3424
3425 siglen = pktout.length - 5 + 4 + 20;
32874aea 3426 len = 1; /* message type */
3427 len += 4 + pklen; /* key blob */
3428 len += 4 + siglen; /* data to sign */
3429 len += 4; /* flags */
1983e559 3430 agentreq = smalloc(4 + len);
3431 PUT_32BIT(agentreq, len);
3432 q = agentreq + 4;
3433 *q++ = SSH2_AGENTC_SIGN_REQUEST;
32874aea 3434 PUT_32BIT(q, pklen);
3435 q += 4;
3436 memcpy(q, pkblob, pklen);
3437 q += pklen;
3438 PUT_32BIT(q, siglen);
3439 q += 4;
1983e559 3440 /* Now the data to be signed... */
32874aea 3441 PUT_32BIT(q, 20);
3442 q += 4;
3443 memcpy(q, ssh2_session_id, 20);
3444 q += 20;
3445 memcpy(q, pktout.data + 5, pktout.length - 5);
3446 q += pktout.length - 5;
1983e559 3447 /* And finally the (zero) flags word. */
3448 PUT_32BIT(q, 0);
2d466ffd 3449 agent_query(agentreq, len + 4, &vret, &retlen);
3450 ret = vret;
1983e559 3451 sfree(agentreq);
3452 if (ret) {
3453 if (ret[4] == SSH2_AGENT_SIGN_RESPONSE) {
3454 logevent("Sending Pageant's response");
3455 ssh2_pkt_addstring_start();
32874aea 3456 ssh2_pkt_addstring_data(ret + 9,
3457 GET_32BIT(ret +
3458 5));
1983e559 3459 ssh2_pkt_send();
3460 authed = TRUE;
3461 break;
3462 } else {
32874aea 3463 logevent
3464 ("Pageant failed to answer challenge");
1983e559 3465 sfree(ret);
3466 }
3467 }
3468 }
3469 if (authed)
3470 continue;
3471 }
3472 }
3473
32874aea 3474 if (!method && can_pubkey && *cfg.keyfile
3475 && !tried_pubkey_config) {
1408a877 3476 unsigned char *pub_blob;
3477 char *algorithm, *comment;
3478 int pub_blob_len;
65a22376 3479
1408a877 3480 tried_pubkey_config = TRUE;
65a22376 3481
65a22376 3482 /*
1408a877 3483 * Try the public key supplied in the configuration.
3484 *
3485 * First, offer the public blob to see if the server is
3486 * willing to accept it.
65a22376 3487 */
1408a877 3488 pub_blob = ssh2_userkey_loadpub(cfg.keyfile, &algorithm,
3489 &pub_blob_len);
3490 if (pub_blob) {
3491 ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
3492 ssh2_pkt_addstring(username);
32874aea 3493 ssh2_pkt_addstring("ssh-connection"); /* service requested */
3494 ssh2_pkt_addstring("publickey"); /* method */
3495 ssh2_pkt_addbool(FALSE); /* no signature included */
1408a877 3496 ssh2_pkt_addstring(algorithm);
3497 ssh2_pkt_addstring_start();
3498 ssh2_pkt_addstring_data(pub_blob, pub_blob_len);
3499 ssh2_pkt_send();
32874aea 3500 logevent("Offered public key"); /* FIXME */
1408a877 3501
3502 crWaitUntilV(ispkt);
3503 if (pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
3504 gotit = TRUE;
3505 type = AUTH_TYPE_PUBLICKEY_OFFER_LOUD;
32874aea 3506 continue; /* key refused; give up on it */
1408a877 3507 }
65a22376 3508
1408a877 3509 logevent("Offer of public key accepted");
65a22376 3510 /*
1408a877 3511 * Actually attempt a serious authentication using
3512 * the key.
65a22376 3513 */
1408a877 3514 if (ssh2_userkey_encrypted(cfg.keyfile, &comment)) {
32874aea 3515 sprintf(pwprompt,
3516 "Passphrase for key \"%.100s\": ",
3517 comment);
1408a877 3518 need_pw = TRUE;
3519 } else {
3520 need_pw = FALSE;
3521 }
3522 c_write_str("Authenticating with public key \"");
3523 c_write_str(comment);
3524 c_write_str("\"\r\n");
3525 method = AUTH_PUBLICKEY_FILE;
65a22376 3526 }
1408a877 3527 }
3528
3529 if (!method && can_passwd) {
3530 method = AUTH_PASSWORD;
32874aea 3531 sprintf(pwprompt, "%.90s@%.90s's password: ", username,
3532 savedhost);
1408a877 3533 need_pw = TRUE;
3534 }
3535
3536 if (need_pw) {
fa17a66e 3537 if (ssh_get_line) {
3538 if (!ssh_get_line(pwprompt, password,
32874aea 3539 sizeof(password), TRUE)) {
1408a877 3540 /*
fa17a66e 3541 * get_line failed to get a password (for
3542 * example because one was supplied on the
3543 * command line which has already failed to
3544 * work). Terminate.
1408a877 3545 */
2bc6a386 3546 ssh2_pkt_init(SSH2_MSG_DISCONNECT);
3547 ssh2_pkt_adduint32(SSH2_DISCONNECT_BY_APPLICATION);
3548 ssh2_pkt_addstring
3549 ("No more passwords available to try");
3550 ssh2_pkt_addstring("en"); /* language tag */
3551 ssh2_pkt_send();
3552 connection_fatal("Unable to authenticate");
1408a877 3553 ssh_state = SSH_STATE_CLOSED;
3554 crReturnV;
3555 }
3556 } else {
3557 static int pos = 0;
3558 static char c;
3559
3560 c_write_str(pwprompt);
3561 ssh_send_ok = 1;
3562
3563 pos = 0;
3564 while (pos >= 0) {
3565 crWaitUntilV(!ispkt);
32874aea 3566 while (inlen--)
3567 switch (c = *in++) {
3568 case 10:
3569 case 13:
3570 password[pos] = 0;
3571 pos = -1;
3572 break;
3573 case 8:
3574 case 127:
3575 if (pos > 0)
3576 pos--;
3577 break;
3578 case 21:
3579 case 27:
3580 pos = 0;
3581 break;
3582 case 3:
3583 case 4:
3584 random_save_seed();
3585 exit(0);
3586 break;
3587 default:
51b2fb65 3588 if (pos < sizeof(password)-1)
32874aea 3589 password[pos++] = c;
3590 break;
3591 }
65a22376 3592 }
1408a877 3593 c_write_str("\r\n");
65a22376 3594 }
65a22376 3595 }
65a22376 3596
1408a877 3597 if (method == AUTH_PUBLICKEY_FILE) {
3598 /*
3599 * We have our passphrase. Now try the actual authentication.
3600 */
3601 struct ssh2_userkey *key;
65a22376 3602
1408a877 3603 key = ssh2_load_userkey(cfg.keyfile, password);
3604 if (key == SSH2_WRONG_PASSPHRASE || key == NULL) {
3605 if (key == SSH2_WRONG_PASSPHRASE) {
3606 c_write_str("Wrong passphrase\r\n");
3607 tried_pubkey_config = FALSE;
3608 } else {
3609 c_write_str("Unable to load private key\r\n");
3610 tried_pubkey_config = TRUE;
3611 }
3612 /* Send a spurious AUTH_NONE to return to the top. */
3613 ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
3614 ssh2_pkt_addstring(username);
32874aea 3615 ssh2_pkt_addstring("ssh-connection"); /* service requested */
3616 ssh2_pkt_addstring("none"); /* method */
1408a877 3617 ssh2_pkt_send();
3618 type = AUTH_TYPE_NONE;
3619 } else {
3620 unsigned char *blob, *sigdata;
3621 int blob_len, sigdata_len;
65a22376 3622
1408a877 3623 /*
3624 * We have loaded the private key and the server
3625 * has announced that it's willing to accept it.
3626 * Hallelujah. Generate a signature and send it.
3627 */
3628 ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
3629 ssh2_pkt_addstring(username);
32874aea 3630 ssh2_pkt_addstring("ssh-connection"); /* service requested */
3631 ssh2_pkt_addstring("publickey"); /* method */
1408a877 3632 ssh2_pkt_addbool(TRUE);
3633 ssh2_pkt_addstring(key->alg->name);
3634 blob = key->alg->public_blob(key->data, &blob_len);
3635 ssh2_pkt_addstring_start();
3636 ssh2_pkt_addstring_data(blob, blob_len);
3637 sfree(blob);
3638
3639 /*
3640 * The data to be signed is:
3641 *
3642 * string session-id
3643 *
3644 * followed by everything so far placed in the
3645 * outgoing packet.
3646 */
3647 sigdata_len = pktout.length - 5 + 4 + 20;
3648 sigdata = smalloc(sigdata_len);
3649 PUT_32BIT(sigdata, 20);
32874aea 3650 memcpy(sigdata + 4, ssh2_session_id, 20);
3651 memcpy(sigdata + 24, pktout.data + 5,
3652 pktout.length - 5);
3653 blob =
3654 key->alg->sign(key->data, sigdata, sigdata_len,
3655 &blob_len);
1408a877 3656 ssh2_pkt_addstring_start();
3657 ssh2_pkt_addstring_data(blob, blob_len);
3658 sfree(blob);
3659 sfree(sigdata);
3660
3661 ssh2_pkt_send();
3662 type = AUTH_TYPE_PUBLICKEY;
3663 }
3664 } else if (method == AUTH_PASSWORD) {
65a22376 3665 /*
1408a877 3666 * We send the password packet lumped tightly together with
3667 * an SSH_MSG_IGNORE packet. The IGNORE packet contains a
3668 * string long enough to make the total length of the two
3669 * packets constant. This should ensure that a passive
3670 * listener doing traffic analyis can't work out the length
3671 * of the password.
3672 *
3673 * For this to work, we need an assumption about the
3674 * maximum length of the password packet. I think 256 is
3675 * pretty conservative. Anyone using a password longer than
3676 * that probably doesn't have much to worry about from
3677 * people who find out how long their password is!
65a22376 3678 */
3679 ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
3680 ssh2_pkt_addstring(username);
32874aea 3681 ssh2_pkt_addstring("ssh-connection"); /* service requested */
1408a877 3682 ssh2_pkt_addstring("password");
3683 ssh2_pkt_addbool(FALSE);
3684 ssh2_pkt_addstring(password);
3685 ssh2_pkt_defer();
65a22376 3686 /*
1408a877 3687 * We'll include a string that's an exact multiple of the
3688 * cipher block size. If the cipher is NULL for some
3689 * reason, we don't do this trick at all because we gain
3690 * nothing by it.
65a22376 3691 */
32874aea 3692 if (cscipher) {
3693 int stringlen, i;
3694
3695 stringlen = (256 - deferred_len);
3696 stringlen += cscipher->blksize - 1;
3697 stringlen -= (stringlen % cscipher->blksize);
3698 if (cscomp) {
3699 /*
3700 * Temporarily disable actual compression,
3701 * so we can guarantee to get this string
3702 * exactly the length we want it. The
3703 * compression-disabling routine should
3704 * return an integer indicating how many
3705 * bytes we should adjust our string length
3706 * by.
3707 */
3708 stringlen -= cscomp->disable_compression();
3709 }
1408a877 3710 ssh2_pkt_init(SSH2_MSG_IGNORE);
3711 ssh2_pkt_addstring_start();
6e9e9520 3712 for (i = 0; i < stringlen; i++) {
32874aea 3713 char c = (char) random_byte();
3714 ssh2_pkt_addstring_data(&c, 1);
65a22376 3715 }
1408a877 3716 ssh2_pkt_defer();
65a22376 3717 }
39065bed 3718 ssh_pkt_defersend();
0d43337a 3719 logevent("Sent password");
1408a877 3720 type = AUTH_TYPE_PASSWORD;
3721 } else {
32874aea 3722 c_write_str
3723 ("No supported authentication methods left to try!\r\n");
3724 logevent
3725 ("No supported authentications offered. Disconnecting");
1408a877 3726 ssh2_pkt_init(SSH2_MSG_DISCONNECT);
3727 ssh2_pkt_adduint32(SSH2_DISCONNECT_BY_APPLICATION);
32874aea 3728 ssh2_pkt_addstring
3729 ("No supported authentication methods available");
3730 ssh2_pkt_addstring("en"); /* language tag */
1408a877 3731 ssh2_pkt_send();
3732 ssh_state = SSH_STATE_CLOSED;
3733 crReturnV;
65a22376 3734 }
65a22376 3735 }
1408a877 3736 } while (!we_are_in);
7cca0d81 3737
3738 /*
3739 * Now we're authenticated for the connection protocol. The
3740 * connection protocol will automatically have started at this
3741 * point; there's no need to send SERVICE_REQUEST.
3742 */
3743
3744 /*
3745 * So now create a channel with a session in it.
3746 */
d2371c81 3747 ssh_channels = newtree234(ssh_channelcmp);
dcbde236 3748 mainchan = smalloc(sizeof(struct ssh_channel));
d2371c81 3749 mainchan->localid = alloc_channel_id();
7cca0d81 3750 ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN);
3751 ssh2_pkt_addstring("session");
d211621f 3752 ssh2_pkt_adduint32(mainchan->localid);
32874aea 3753 ssh2_pkt_adduint32(0x8000UL); /* our window size */
3754 ssh2_pkt_adduint32(0x4000UL); /* our max pkt size */
7cca0d81 3755 ssh2_pkt_send();
3756 crWaitUntilV(ispkt);
3757 if (pktin.type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
32874aea 3758 bombout(("Server refused to open a session"));
3759 crReturnV;
3760 /* FIXME: error data comes back in FAILURE packet */
7cca0d81 3761 }
d211621f 3762 if (ssh2_pkt_getuint32() != mainchan->localid) {
32874aea 3763 bombout(("Server's channel confirmation cited wrong channel"));
3764 crReturnV;
7cca0d81 3765 }
d211621f 3766 mainchan->remoteid = ssh2_pkt_getuint32();
783415f8 3767 mainchan->type = CHAN_MAINSESSION;
3768 mainchan->closes = 0;
3769 mainchan->v2.remwindow = ssh2_pkt_getuint32();
3770 mainchan->v2.remmaxpkt = ssh2_pkt_getuint32();
3771 mainchan->v2.outbuffer = NULL;
3772 mainchan->v2.outbuflen = mainchan->v2.outbufsize = 0;
783415f8 3773 add234(ssh_channels, mainchan);
7cca0d81 3774 logevent("Opened channel for session");
3775
3776 /*
783415f8 3777 * Potentially enable X11 forwarding.
3778 */
3779 if (cfg.x11_forward) {
32874aea 3780 char proto[20], data[64];
3781 logevent("Requesting X11 forwarding");
3782 x11_invent_auth(proto, sizeof(proto), data, sizeof(data));
3783 ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
3784 ssh2_pkt_adduint32(mainchan->remoteid);
3785 ssh2_pkt_addstring("x11-req");
3786 ssh2_pkt_addbool(1); /* want reply */
3787 ssh2_pkt_addbool(0); /* many connections */
3788 ssh2_pkt_addstring(proto);
3789 ssh2_pkt_addstring(data);
3790 ssh2_pkt_adduint32(0); /* screen number */
3791 ssh2_pkt_send();
3792
3793 do {
3794 crWaitUntilV(ispkt);
3795 if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
3796 unsigned i = ssh2_pkt_getuint32();
3797 struct ssh_channel *c;
3798 c = find234(ssh_channels, &i, ssh_channelfind);
3799 if (!c)
3800 continue; /* nonexistent channel */
3801 c->v2.remwindow += ssh2_pkt_getuint32();
3802 }
3803 } while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
3804
3805 if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
3806 if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
3807 bombout(("Server got confused by X11 forwarding request"));
3808 crReturnV;
3809 }
3810 logevent("X11 forwarding refused");
3811 } else {
3812 logevent("X11 forwarding enabled");
783415f8 3813 ssh_X11_fwd_enabled = TRUE;
32874aea 3814 }
783415f8 3815 }
3816
3817 /*
36c2a3e9 3818 * Potentially enable agent forwarding.
3819 */
3820 if (cfg.agentfwd && agent_exists()) {
32874aea 3821 logevent("Requesting OpenSSH-style agent forwarding");
3822 ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
3823 ssh2_pkt_adduint32(mainchan->remoteid);
3824 ssh2_pkt_addstring("auth-agent-req@openssh.com");
3825 ssh2_pkt_addbool(1); /* want reply */
3826 ssh2_pkt_send();
3827
3828 do {
3829 crWaitUntilV(ispkt);
3830 if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
3831 unsigned i = ssh2_pkt_getuint32();
3832 struct ssh_channel *c;
3833 c = find234(ssh_channels, &i, ssh_channelfind);
3834 if (!c)
3835 continue; /* nonexistent channel */
3836 c->v2.remwindow += ssh2_pkt_getuint32();
3837 }
3838 } while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
3839
3840 if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
3841 if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
3842 bombout(
3843 ("Server got confused by agent forwarding request"));
3844 crReturnV;
3845 }
3846 logevent("Agent forwarding refused");
3847 } else {
3848 logevent("Agent forwarding enabled");
36c2a3e9 3849 ssh_agentfwd_enabled = TRUE;
32874aea 3850 }
36c2a3e9 3851 }
3852
3853 /*
7cca0d81 3854 * Now allocate a pty for the session.
3855 */
67779be7 3856 if (!cfg.nopty) {
32874aea 3857 ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
3858 ssh2_pkt_adduint32(mainchan->remoteid); /* recipient channel */
3859 ssh2_pkt_addstring("pty-req");
3860 ssh2_pkt_addbool(1); /* want reply */
3861 ssh2_pkt_addstring(cfg.termtype);
3862 ssh2_pkt_adduint32(cols);
3863 ssh2_pkt_adduint32(rows);
3864 ssh2_pkt_adduint32(0); /* pixel width */
3865 ssh2_pkt_adduint32(0); /* pixel height */
3866 ssh2_pkt_addstring_start();
3867 ssh2_pkt_addstring_data("\0", 1); /* TTY_OP_END, no special options */
3868 ssh2_pkt_send();
3869 ssh_state = SSH_STATE_INTERMED;
3870
3871 do {
3872 crWaitUntilV(ispkt);
3873 if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
3874 unsigned i = ssh2_pkt_getuint32();
3875 struct ssh_channel *c;
3876 c = find234(ssh_channels, &i, ssh_channelfind);
3877 if (!c)
3878 continue; /* nonexistent channel */
3879 c->v2.remwindow += ssh2_pkt_getuint32();
3880 }
3881 } while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
3882
3883 if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
3884 if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
3885 bombout(("Server got confused by pty request"));
3886 crReturnV;
3887 }
3888 c_write_str("Server refused to allocate pty\r\n");
3889 ssh_editing = ssh_echoing = 1;
3890 } else {
3891 logevent("Allocated pty");
3892 }
0965bee0 3893 } else {
32874aea 3894 ssh_editing = ssh_echoing = 1;
7cca0d81 3895 }
3896
3897 /*
67779be7 3898 * Start a shell or a remote command.
7cca0d81 3899 */
3900 ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
32874aea 3901 ssh2_pkt_adduint32(mainchan->remoteid); /* recipient channel */
4a8fc3c4 3902 if (cfg.ssh_subsys) {
32874aea 3903 ssh2_pkt_addstring("subsystem");
3904 ssh2_pkt_addbool(1); /* want reply */
3905 ssh2_pkt_addstring(cfg.remote_cmd_ptr);
96621a84 3906 } else if (*cfg.remote_cmd_ptr) {
32874aea 3907 ssh2_pkt_addstring("exec");
3908 ssh2_pkt_addbool(1); /* want reply */
3909 ssh2_pkt_addstring(cfg.remote_cmd_ptr);
67779be7 3910 } else {
32874aea 3911 ssh2_pkt_addstring("shell");
3912 ssh2_pkt_addbool(1); /* want reply */
67779be7 3913 }
7cca0d81 3914 ssh2_pkt_send();
d211621f 3915 do {
32874aea 3916 crWaitUntilV(ispkt);
3917 if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
3918 unsigned i = ssh2_pkt_getuint32();
3919 struct ssh_channel *c;
3920 c = find234(ssh_channels, &i, ssh_channelfind);
3921 if (!c)
3922 continue; /* nonexistent channel */
3923 c->v2.remwindow += ssh2_pkt_getuint32();
3924 }
7cca0d81 3925 } while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
3926 if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
32874aea 3927 if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
3928 bombout(("Server got confused by shell/command request"));
3929 crReturnV;
3930 }
3931 bombout(("Server refused to start a shell/command"));
3932 crReturnV;
7cca0d81 3933 } else {
32874aea 3934 logevent("Started a shell/command");
7cca0d81 3935 }
3936
6e48c3fe 3937 ssh_state = SSH_STATE_SESSION;
3938 if (size_needed)
3939 ssh_size();
3687d221 3940 if (eof_needed)
32874aea 3941 ssh_special(TS_EOF);
6e48c3fe 3942
7cca0d81 3943 /*
3944 * Transfer data!
3945 */
32874aea 3946 ldisc_send(NULL, 0); /* cause ldisc to notice changes */
8ccc75b0 3947 ssh_send_ok = 1;
7cca0d81 3948 while (1) {
32874aea 3949 static int try_send;
e5574168 3950 crReturnV;
32874aea 3951 try_send = FALSE;
7cca0d81 3952 if (ispkt) {
3953 if (pktin.type == SSH2_MSG_CHANNEL_DATA ||
32874aea 3954 pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA) {
3955 char *data;
3956 int length;
3957 unsigned i = ssh2_pkt_getuint32();
3958 struct ssh_channel *c;
3959 c = find234(ssh_channels, &i, ssh_channelfind);
3960 if (!c)
3961 continue; /* nonexistent channel */
3962 if (pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA &&
3963 ssh2_pkt_getuint32() != SSH2_EXTENDED_DATA_STDERR)
3964 continue; /* extended but not stderr */
3965 ssh2_pkt_getstring(&data, &length);
3966 if (data) {
3967 switch (c->type) {
3968 case CHAN_MAINSESSION:
3969 from_backend(pktin.type ==
3970 SSH2_MSG_CHANNEL_EXTENDED_DATA, data,
3971 length);
3972 break;
3973 case CHAN_X11:
3974 x11_send(c->u.x11.s, data, length);
3975 break;
36c2a3e9 3976 case CHAN_AGENT:
32874aea 3977 while (length > 0) {
3978 if (c->u.a.lensofar < 4) {
3979 int l = min(4 - c->u.a.lensofar, length);
3980 memcpy(c->u.a.msglen + c->u.a.lensofar,
3981 data, l);
3982 data += l;
3983 length -= l;
3984 c->u.a.lensofar += l;
3985 }
3986 if (c->u.a.lensofar == 4) {
3987 c->u.a.totallen =
3988 4 + GET_32BIT(c->u.a.msglen);
3989 c->u.a.message = smalloc(c->u.a.totallen);
3990 memcpy(c->u.a.message, c->u.a.msglen, 4);
3991 }
3992 if (c->u.a.lensofar >= 4 && length > 0) {
3993 int l =
3994 min(c->u.a.totallen - c->u.a.lensofar,
3995 length);
3996 memcpy(c->u.a.message + c->u.a.lensofar,
3997 data, l);
3998 data += l;
3999 length -= l;
4000 c->u.a.lensofar += l;
4001 }
4002 if (c->u.a.lensofar == c->u.a.totallen) {
4003 void *reply, *sentreply;
4004 int replylen;
4005 agent_query(c->u.a.message,
4006 c->u.a.totallen, &reply,
4007 &replylen);
4008 if (reply)
4009 sentreply = reply;
4010 else {
4011 /* Fake SSH_AGENT_FAILURE. */
4012 sentreply = "\0\0\0\1\5";
4013 replylen = 5;
4014 }
4015 ssh2_add_channel_data(c, sentreply,
4016 replylen);
36c2a3e9 4017 try_send = TRUE;
32874aea 4018 if (reply)
4019 sfree(reply);
4020 sfree(c->u.a.message);
4021 c->u.a.lensofar = 0;
4022 }
4023 }
4024 break;
4025 }
4026 /*
4027 * Enlarge the window again at the remote
4028 * side, just in case it ever runs down and
4029 * they fail to send us any more data.
4030 */
4031 ssh2_pkt_init(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
4032 ssh2_pkt_adduint32(c->remoteid);
4033 ssh2_pkt_adduint32(length);
4034 ssh2_pkt_send();
4035 }
7cca0d81 4036 } else if (pktin.type == SSH2_MSG_DISCONNECT) {
32874aea 4037 ssh_state = SSH_STATE_CLOSED;
d211621f 4038 logevent("Received disconnect message");
32874aea 4039 crReturnV;
7cca0d81 4040 } else if (pktin.type == SSH2_MSG_CHANNEL_REQUEST) {
32874aea 4041 continue; /* exit status et al; ignore (FIXME?) */
d211621f 4042 } else if (pktin.type == SSH2_MSG_CHANNEL_EOF) {
32874aea 4043 unsigned i = ssh2_pkt_getuint32();
4044 struct ssh_channel *c;
4045
4046 c = find234(ssh_channels, &i, ssh_channelfind);
4047 if (!c)
4048 continue; /* nonexistent channel */
4049
4050 if (c->type == CHAN_X11) {
4051 /*
4052 * Remote EOF on an X11 channel means we should
4053 * wrap up and close the channel ourselves.
4054 */
4055 x11_close(c->u.x11.s);
4056 sshfwd_close(c);
4057 } else if (c->type == CHAN_AGENT) {
36c2a3e9 4058 sshfwd_close(c);
4059 }
d211621f 4060 } else if (pktin.type == SSH2_MSG_CHANNEL_CLOSE) {
32874aea 4061 unsigned i = ssh2_pkt_getuint32();
4062 struct ssh_channel *c;
4063
4064 c = find234(ssh_channels, &i, ssh_channelfind);
4065 if (!c)
4066 continue; /* nonexistent channel */
4067 if (c->closes == 0) {
4068 ssh2_pkt_init(SSH2_MSG_CHANNEL_CLOSE);
4069 ssh2_pkt_adduint32(c->remoteid);
4070 ssh2_pkt_send();
4071 }
4072 /* Do pre-close processing on the channel. */
4073 switch (c->type) {
4074 case CHAN_MAINSESSION:
4075 break; /* nothing to see here, move along */
4076 case CHAN_X11:
4077 break;
4078 case CHAN_AGENT:
4079 break;
4080 }
4081 del234(ssh_channels, c);
4082 sfree(c->v2.outbuffer);
4083 sfree(c);
4084
4085 /*
4086 * See if that was the last channel left open.
4087 */
4088 if (count234(ssh_channels) == 0) {
4089 logevent("All channels closed. Disconnecting");
4090 ssh2_pkt_init(SSH2_MSG_DISCONNECT);
4091 ssh2_pkt_adduint32(SSH2_DISCONNECT_BY_APPLICATION);
4092 ssh2_pkt_addstring("All open channels closed");
4093 ssh2_pkt_addstring("en"); /* language tag */
4094 ssh2_pkt_send();
4095 ssh_state = SSH_STATE_CLOSED;
4096 crReturnV;
4097 }
4098 continue; /* remote sends close; ignore (FIXME) */
7cca0d81 4099 } else if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
32874aea 4100 unsigned i = ssh2_pkt_getuint32();
4101 struct ssh_channel *c;
4102 c = find234(ssh_channels, &i, ssh_channelfind);
4103 if (!c)
4104 continue; /* nonexistent channel */
4105 c->v2.remwindow += ssh2_pkt_getuint32();
4106 try_send = TRUE;
783415f8 4107 } else if (pktin.type == SSH2_MSG_CHANNEL_OPEN) {
32874aea 4108 char *type;
4109 int typelen;
4110 char *error = NULL;
4111 struct ssh_channel *c;
4112 ssh2_pkt_getstring(&type, &typelen);
4113 c = smalloc(sizeof(struct ssh_channel));
4114
4115 if (typelen == 3 && !memcmp(type, "x11", 3)) {
4116 if (!ssh_X11_fwd_enabled)
4117 error = "X11 forwarding is not enabled";
4118 else if (x11_init(&c->u.x11.s, cfg.x11_display, c) !=
4119 NULL) {
4120 error = "Unable to open an X11 connection";
4121 } else {
4122 c->type = CHAN_X11;
4123 }
4124 } else if (typelen == 22 &&
36c2a3e9 4125 !memcmp(type, "auth-agent@openssh.com", 3)) {
32874aea 4126 if (!ssh_agentfwd_enabled)
4127 error = "Agent forwarding is not enabled";
36c2a3e9 4128 else {
32874aea 4129 c->type = CHAN_AGENT; /* identify channel type */
36c2a3e9 4130 c->u.a.lensofar = 0;
32874aea 4131 }
4132 } else {
4133 error = "Unsupported channel type requested";
4134 }
4135
4136 c->remoteid = ssh2_pkt_getuint32();
4137 if (error) {
4138 ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN_FAILURE);
4139 ssh2_pkt_adduint32(c->remoteid);
4140 ssh2_pkt_adduint32(SSH2_OPEN_CONNECT_FAILED);
4141 ssh2_pkt_addstring(error);
4142 ssh2_pkt_addstring("en"); /* language tag */
4143 ssh2_pkt_send();
4144 sfree(c);
4145 } else {
4146 c->localid = alloc_channel_id();
4147 c->closes = 0;
4148 c->v2.remwindow = ssh2_pkt_getuint32();
4149 c->v2.remmaxpkt = ssh2_pkt_getuint32();
4150 c->v2.outbuffer = NULL;
4151 c->v2.outbuflen = c->v2.outbufsize = 0;
4152 add234(ssh_channels, c);
4153 ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
4154 ssh2_pkt_adduint32(c->remoteid);
4155 ssh2_pkt_adduint32(c->localid);
4156 ssh2_pkt_adduint32(0x8000UL); /* our window size */
4157 ssh2_pkt_adduint32(0x4000UL); /* our max pkt size */
4158 ssh2_pkt_send();
4159 }
7cca0d81 4160 } else {
8d5de777 4161 bombout(("Strange packet received: type %d", pktin.type));
32874aea 4162 crReturnV;
7cca0d81 4163 }
4164 } else {
32874aea 4165 /*
4166 * We have spare data. Add it to the channel buffer.
4167 */
4168 ssh2_add_channel_data(mainchan, in, inlen);
4169 try_send = TRUE;
4170 }
4171 if (try_send) {
4172 int i;
4173 struct ssh_channel *c;
4174 /*
4175 * Try to send data on all channels if we can.
4176 */
4177 for (i = 0; NULL != (c = index234(ssh_channels, i)); i++)
4178 ssh2_try_send(c);
7cca0d81 4179 }
e5574168 4180 }
4181
4182 crFinishV;
4183}
4184
4185/*
7cca0d81 4186 * Handle the top-level SSH2 protocol.
4187 */
4188static void ssh2_protocol(unsigned char *in, int inlen, int ispkt)
4189{
4190 if (do_ssh2_transport(in, inlen, ispkt) == 0)
32874aea 4191 return;
7cca0d81 4192 do_ssh2_authconn(in, inlen, ispkt);
4193}
4194
4195/*
8df7a775 4196 * Called to set up the connection.
374330e2 4197 *
4198 * Returns an error message, or NULL on success.
374330e2 4199 */
32874aea 4200static char *ssh_init(char *host, int port, char **realhost)
4201{
fb09bf1c 4202 char *p;
32874aea 4203
8f203108 4204#ifdef MSCRYPTOAPI
32874aea 4205 if (crypto_startup() == 0)
8f203108 4206 return "Microsoft high encryption pack not installed!";
4207#endif
374330e2 4208
8df7a775 4209 ssh_send_ok = 0;
0965bee0 4210 ssh_editing = 0;
4211 ssh_echoing = 0;
8df7a775 4212
fb09bf1c 4213 p = connect_to_host(host, port, realhost);
4214 if (p != NULL)
4215 return p;
374330e2 4216
374330e2 4217 return NULL;
4218}
4219
4220/*
374330e2 4221 * Called to send data down the Telnet connection.
4222 */
32874aea 4223static void ssh_send(char *buf, int len)
4224{
f78051a1 4225 if (s == NULL || ssh_protocol == NULL)
374330e2 4226 return;
4227
4228 ssh_protocol(buf, len, 0);
4229}
4230
4231/*
6e48c3fe 4232 * Called to set the size of the window from SSH's POV.
374330e2 4233 */
32874aea 4234static void ssh_size(void)
4235{
374330e2 4236 switch (ssh_state) {
4237 case SSH_STATE_BEFORE_SIZE:
3687d221 4238 case SSH_STATE_PREPACKET:
21248260 4239 case SSH_STATE_CLOSED:
374330e2 4240 break; /* do nothing */
4241 case SSH_STATE_INTERMED:
4242 size_needed = TRUE; /* buffer for later */
4243 break;
4244 case SSH_STATE_SESSION:
32874aea 4245 if (!cfg.nopty) {
4246 if (ssh_version == 1) {
4247 send_packet(SSH1_CMSG_WINDOW_SIZE,
4248 PKT_INT, rows, PKT_INT, cols,
4249 PKT_INT, 0, PKT_INT, 0, PKT_END);
4250 } else {
4251 ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
4252 ssh2_pkt_adduint32(mainchan->remoteid);
4253 ssh2_pkt_addstring("window-change");
4254 ssh2_pkt_addbool(0);
4255 ssh2_pkt_adduint32(cols);
4256 ssh2_pkt_adduint32(rows);
4257 ssh2_pkt_adduint32(0);
4258 ssh2_pkt_adduint32(0);
4259 ssh2_pkt_send();
4260 }
4261 }
4262 break;
374330e2 4263 }
4264}
4265
4266/*
6abbf9e3 4267 * Send Telnet special codes. TS_EOF is useful for `plink', so you
4268 * can send an EOF and collect resulting output (e.g. `plink
4269 * hostname sort').
374330e2 4270 */
32874aea 4271static void ssh_special(Telnet_Special code)
4272{
6abbf9e3 4273 if (code == TS_EOF) {
32874aea 4274 if (ssh_state != SSH_STATE_SESSION) {
4275 /*
4276 * Buffer the EOF in case we are pre-SESSION, so we can
4277 * send it as soon as we reach SESSION.
4278 */
4279 if (code == TS_EOF)
4280 eof_needed = TRUE;
4281 return;
4282 }
4283 if (ssh_version == 1) {
4284 send_packet(SSH1_CMSG_EOF, PKT_END);
4285 } else {
4286 ssh2_pkt_init(SSH2_MSG_CHANNEL_EOF);
4287 ssh2_pkt_adduint32(mainchan->remoteid);
4288 ssh2_pkt_send();
4289 }
4290 logevent("Sent EOF message");
ec55b220 4291 } else if (code == TS_PING) {
32874aea 4292 if (ssh_state == SSH_STATE_CLOSED
4293 || ssh_state == SSH_STATE_PREPACKET) return;
4294 if (ssh_version == 1) {
4295 send_packet(SSH1_MSG_IGNORE, PKT_STR, "", PKT_END);
4296 } else {
4297 ssh2_pkt_init(SSH2_MSG_IGNORE);
4298 ssh2_pkt_addstring_start();
4299 ssh2_pkt_send();
4300 }
6abbf9e3 4301 } else {
32874aea 4302 /* do nothing */
6abbf9e3 4303 }
374330e2 4304}
4305
32874aea 4306static Socket ssh_socket(void)
4307{
4308 return s;
4309}
8ccc75b0 4310
32874aea 4311static int ssh_sendok(void)
4312{
4313 return ssh_send_ok;
4314}
fb09bf1c 4315
32874aea 4316static int ssh_ldisc(int option)
4317{
4318 if (option == LD_ECHO)
4319 return ssh_echoing;
4320 if (option == LD_EDIT)
4321 return ssh_editing;
0965bee0 4322 return FALSE;
4323}
4324
374330e2 4325Backend ssh_backend = {
4326 ssh_init,
374330e2 4327 ssh_send,
4328 ssh_size,
4017be6d 4329 ssh_special,
8ccc75b0 4330 ssh_socket,
97db3be4 4331 ssh_sendok,
0965bee0 4332 ssh_ldisc,
97db3be4 4333 22
374330e2 4334};
Local modifications for Simon Tatham's `PuTTY' SSH client and terminal emulator